Quinze cães, sem raça definida, de ambos os sexos, de peso entre 18 e 25kg, foram submetidos à secção artroscópica do ligamento cruzado cranial (LCCr) para indução da doença articular degenerativa (DAD). Após três semanas de instabilidade articular, o LCCr foi substituído pela fáscia lata segundo a técnica de Schwalder (1989) e os animais foram distribuídos em três grupos de cinco. Os animais do grupo I, controle, não receberam tratamento medicamentoso; os do grupo II, 24mg/animal de sulfato de condroitina, por via IM, de cinco em cinco dias, totalizando seis aplicações; e os do grupo III foram tratados com hialuronato de sódio na dose de 20mg/animal, por via IV, de cinco em cinco dias num total de três administrações. Ao final de 90 dias, os animais foram eutanasiados e procedeu-se à colheita e ao processamento histológico da membrana sinovial e da cartilagem articular para avaliações morfológica e morfométrica. No grupo I foram observadas alterações degenerativas de DAD mais acentuadas que nos demais grupos, como redução do número de condrócitos, presença de pânus, fibrilações, fissuras, erosões e irregularidades na superfície articular. No grupo II observou-se elevação do número de condrócitos com aumento da atividade de síntese da matriz e redução das lesões na superfície da cartilagem. No grupo III houve aumento do número de condrócitos que eram, muitas vezes, morfologicamente inviáveis. Todos os grupos apresentaram proliferação da membrana sinovial e presença de infiltrado linfoplasmocitário na subíntima e na perivascular. Nos grupos I e III, a proliferação da membrana sinovial era exuberante com formação de pânus, presença de sinoviócitos achatados ou ausência de sinóvia com tecido de granulação. Os resultados sugerem que o sulfato de condroitina estimulou a cartilagem articular, diminuindo ou retardando as alterações da DAD e o hialuronato de sódio não interferiu no processo degenerativo da cartilagem articular. Não foi constatada ação favorável das drogas na membrana sinovial.

Fifteen mongrel dogs, both genders, weighting from 18 to 25kg were used and Degenerative Joint Disease (DJD) was induced through cranial cruciate ligament (CCrL) artroscopical section. After three weeks, CCrL was reconstructed by Schawalder's (1989) technique. Then, dogs were distributed in three groups and the following protocols were used: group I, control, no other treatment but the CCrL reconstruction; group II received chondroitin sulfate 24mg per animal every five days, intramuscularly, in a total of six injections; and group III received sodium hyaluronate 20mg per animal every five days, intravenously, in a total of three injections. Clinical observation was done until 90 days after treatments. By that time, the articular cartilage and synovium were collected and their morphology was evaluated. In group I, the degenerative alterations of the DJD were the most intense. Thus, decrease of chondrocytes number, pannus, fibrillations, grooves, erosion, and irregular articular surface were observed on the cartilage. In group II, raise of chondrocytes number was observed, with increase of synthesis activity of matrix and decrease of lesions on the articular surface. There was an increase of chondrocytes in group III, but the cells were morphologically unviable. All the groups showed proliferation of the synovial membrane, with limpho-plasma cells infiltrated in subintim and perivascular. In groups I and III, the proliferation of synovium was abundant, with formation of pannus, flattened synoviocytes or synovium absent with granulation tissue. Those results suggest that the chondroitin sulfate stimulated the articular cartilage; decreasing or delaying the alterations of DJD, as well as, the sodium hyaluronate did not interfere on degenerative process in articular cartilage. No favorable action of these drugs in the synovial membrane was verified.

Foram utilizadas amostras de cartilagem articular do fêmur, tíbia e patela de 15 cães com doença articular degenerativa (DAD), induzida experimentalmente. Foram constituídos três grupos de cinco animais: grupo 1 - controle, não medicado; grupo 2 - tratado com sulfato de condroitina e grupo 3 - tratado com hialuronato de sódio. As amostras foram processadas e coradas pelas técnicas de HE e de azul de toluidina para avaliação das alterações morfológicas, e impregnadas pelo nitrato de prata para análise da atividade metabólica e/ou proliferativa dos condrócitos, por meio da visualização e quantificação de regiões organizadoras do nucléolo (NORs). Não foram notadas diferenças significativas (P<0,05) na avaliação morfológica entre os grupos. O grupo tratado com hialuronato obteve maior escore sugerindo maior gravidade das lesões. Não foram observadas diferenças significativas (P>0,05) na contagem de NORs, células e NORs/célula entre os grupos. As maiores contagens de NORs e de células no grupo tratado com hialuronato de sódio sugeriram aumento da taxa de proliferação dos condrócitos. A maior relação de NORs/célula obtida no grupo tratado com sulfato de condroitina sugere que essa droga estimula a atividade metabólica do condrócito, minimizando as lesões ocorridas durante a DAD.

Samples of articular cartilage of femur, tibia and patella of 15 dogs with experimentally induced degenerative joint disease (DJD) were microscopically analyzed. Animals were distributed into three groups (n=5): the control group received no medication; the second group was treated with chondroitin sulfate and the third received sodium hyaluronate. Samples were processed and stained with HE and toluidine blue for morphological evaluation. The metabolic and proliferative activity of the chondrocytes was evaluated by the measurement of nucleolar organizer regions (NORs) after impregnation by silver nitrate. Significant differences were not observed (P>0.05) in the morphology among the groups, however, the group treated with sodium hyaluronate had a higher score suggesting a trend to a greater severity of the lesions. Significant differences were not observed (P>0.05) in the measurement of NORs, cells and NORs/cells among the groups. Although differences were not significant, sodium hyaluronate group showed higher NOR and cell counts which suggested an increase of the proliferation rate of chondrocytes. In addition, a higher NOR/cell ratio in the group treated with chondroitin sulfate suggested that this drug may have stimulated the metabolic activity of the chondrocytes, minimizing the lesions resulting from DJD.

Foram estudadas a histomorfometria e a atividade secretória das tubas uterinas e do útero de 38 ratas Wistar púberes, distribuídas em quatro grupos: (1) eutireóideo em proestro-estro, (2) hipertireóideo em proestro-estro, (3) eutireóideo em metaestro-diestro e (4) hipertireóideo em metaestro-diestro. Posteriormente, foram utilizadas outras 24 ratas Wistar pré-púberes, com 12 dias de idade, distribuídas em dois grupos: (1) hipertireóideo (n=12) e (2) eutireóideo (n=12). O útero e as tubas uterinas foram colhidos para avaliação histomorfométrica e histoquímica. A altura do epitélio da ampola, tanto no proestro-estro quanto no metaestro-diestro, elevou-se com a administração de tiroxina, tornando-se semelhante à do istmo. O hipertireoidismo aumentou a secreção PAS positiva e de mucossubstâncias ácidas do infundíbulo na fase estrogênica, igualando-a à do istmo. A parede uterina apresentou-se mais espessa na fase estrogênica, resultado da ação conjunta da tiroxina no endométrio e no miométrio. A atividade secretória e a composição do colágeno uterino não diferiram entre tratamentos. Nas ratas pré-púberes, o hipertireoidismo aumentou a espessura do miométrio e da parede uterina, mas não alterou a tuba uterina. O hipertireoidismo em ratas pré-púberes induz modificações significativas somente no útero; após a maturidade sexual, as modificações ocorrem no útero e na tuba uterina em intensidade variável e dependentes da fase do ciclo estral.

The histomorphometry and the secretory activity of the uterine tubes and uterus of 38 puberal Wistar rats were studied. Rats were divided in four groups: (1) euthyroid in proestrus-estrus, (2) hyperthyroid in proestrus-estrus, (3) euthyroid in metestrus-diestrus and, (4) hyperthyroid in metestrus-diestrus. In other experiment, 24 prepuberal 12-day-old Wistar rats were divided in two groups: (1) hyperthyroid and (2) euthyroid. The uterus and the uterine tubes were collected for histomorphometry and histochemical analyses. The ampulla's epithelial height has risen under the thyroxine treatment in proestrus-estrus as well as in metestrus-diestrus, becoming similar to the isthmus. The hyperthyroidism increased the PAS positive and acid mucosubstances secretions of the infundibulum on the estrogenic phase coming up to the isthmus. The uterine wall in the estrogenic phase was thicker due to the thyroxine action on the endometrium and myometrium. The secretory activity and uterine collagen composition did not differ between treatments. In puberal rats, the hyperthyroidism increased the thickness of the myometrium and the uterine wall, but did not alter the uterine tubes. Hyperthyroidism on prepuberal rats induced significant changes only in the uterus. After sexual maturity, changes in the uterus and uterine tubes were observed with variable intensity and were dependent on the estrous cycle phase.

Foram estudadas 84 paratireóides de ratas Wistar com cinco meses de idade, castradas ou não, e mantidas em hipertireoidismo por períodos de 30, 60 e 90 dias. Dois grupos eutireóideos, um castrado e o outro não, foram mantidos nas mesmas condições e serviram de controle. Ao final de cada período, foram colhidos o plasma, para determinação da concentração de T4 livre, o cálcio e o fósforo e as paratireóides, para análise morfológica e determinação da porcentagem de núcleo, citoplasma e estroma. Aos 90 dias houve reversão da hipocalcemia observada aos 60 dias nos animais eutireóideos castrados e não castrados, graças à hipertrofia da paratireóide. O mesmo não ocorreu com os grupos hipertireóideos que apresentaram hipocalcemia e hiperfosfatemia progressivas e não compensadas até os 90 dias. Na castração há pronta reversão da hipocalcemia em resposta ao aumento da atividade funcional da paratireóide. No estado hipertireóideo com gônadas funcionais, apesar da hipertrofia da paratireóide, não há retorno à isocalcemia e isofosfatemia. Na associação hipertireoidismo-castração, a paratireóide não responde satisfatoriamente à hipocalcemia e hiperfosfatemia intensas e progressivas.

Eighty four parathyroids of castrated and intact adult female Wistar rats kept under hyperthyroidism state for 30, 60 or 90 days were studied. Two euthyroid goups, one castrated and another intact were used as controls. At the end of each period, blood was collected and the concentrations of free T4, calcium and phosphorus were determined. The parathyroids were analysed microscopically and % of nuclei, cytoplasm and stroma were determined. Hypocalcemia that was observed in castrated and intact euthyroid rats at 60 days was reverted after 90 days due to parathyroid hypertrophy. In hyperthyroid groups, hypocalcemia and hyperphosphatemia were progressive and did not revert at 90 days. In conclusion, castration revert hypocalcemia due to the increase of parathyroid activity. In spite of parathyroid hypertrophy, hyperthyroid state with functional gonads did not return to isocalcemia and isophosphatemia state. In addition, under the association of hyperthyroidism-castration, parathyroid did not respond to progressive hypocalcemia and hyperphosphatemia.

A foliculogênese ovariana foi estudada em ratas adultas Wistar, hipotireóideas na fase de metaestro-diestro. O hipotireoidismo foi induzido pela administração oral e diária de propiltiouracil (1mg/animal). As ratas eutireóideas receberam placebo. Após 120 dias de tratamento, foi colhido o plasma para dosagem de tiroxina livre, progesterona e estradiol após o que foram sacrificadas para colheita dos ovários, tubas e útero, para avaliação histomorfométrica e histoquímica. O hipotireoidismo reduziu significativamente o peso dos ovários e o número de folículos secundários e terciários e de corpos lúteos sem, no entanto, alterar a porcentagem de folículos atrésicos e o número de folículos primários e pré-ovulatórios. As células da granulosa dos folículos secundários das ratas hipotireóideas apresentavam núcleo pequeno com significativa redução do número de regiões organizadoras de nucléolo (NORs). Essas mudanças não alteraram os valores periféricos de estradiol e de progesterona. Houve redução significativa da espessura do endométrio, do número de glândulas endometriais e da altura do epitélio do infundíbulo.

Ovarian folicullogenesis was studied in adult Wistar rats. The animals were hypothyroid in the metaestrus/diestrus phase of the estrous cycle. Hypothyroidism was induced by oral treatment with 1mg/animal of propylthiouracil. Euthyroid rats were kept under the same experimental conditions receiving placebo. After 120 days under treatment, all animals were killed and plasma was taken to assessing free thyroxine, progesterone, and estradiol. The ovaries, tubes and uterus were sampled for histomorphometric and histochemistry evaluation. Hypothyroidism significantly reduced the weight of the ovaries and the number of secondary and tertiary follicles, and corpora luteum. The number of atretic follicles as well as primary and pre-ovulatory follicles was not affected. Granulosa cells in the secondary follicles of treated rats had small nuclei with a reduced number of AgNORs. Significant reduction of the endometrium thickness, number of endometrial glands and the infundibulum epithelium height was observed.

The effect of the estrogenic phase in the bone and in the mineral metabolism was studied in Wistar adult female rats kept under euthyroidism or hyperthyroidism for 60 days. The rats were divided, according to the stage of the estrous cycle, into four groups: 1) euthyroid (proestrus-estrus), 2) euthyroid (metaestrus-diestrus), 3) hyperthyroid (proestrus-estrus), and 4) hyperthyroid (metaestrus-diestrus). After 60 days the blood plasma was collected and the concentrations of free T4, estradiol, progesterone, calcium, phosphorus, and of alkaline phosphatase were determined. The bones (femur and tibia) were analysed microscopically. Despite of the functional state of the thyroid, the levels of estrogen were significantly higher in the proestrus-estrus. The estrogenic phase increased the plasmatic concentration of calcium significantly in the euthyroid rats but it did not alter the levels of phosphorus and alkaline phosphatase. In the hyperthyroid state no significant differences in the plasmatic concentrations of calcium, phosphorus and alkaline phosphatase throughout the cycle were found. The phases of the cycle did not also influence the bone morphology in the euthyroid and hyperthyroid states. It was concluded that the estrogenic phase increases the plasmatic concentration of calcium, even without altering the bone morphology of the euthyroid rats. In addition the estrogenic phase does not increase the plasmatic calcium and it does not modify the response of the bone as well as of the mineral metabolism under effect of the hyperthyroidism.

O presente trabalho objetivou avaliar a associação de hialuronato de sódio e sulfato de condroitina no tratamento da doença articular degenerativa (DAD) em cães. Dez cães sem raça definida foram submetidos à secção artroscópica do ligamento cruzado cranial visando o desenvolvimento da DAD. Após 21 dias, foi substituído cirurgicamente o ligamento cruzado cranial em todos os animais e iniciado o tratamento com associação de hialuronato de sódio e sulfato de condroitina em cinco cães, sendo os remanescentes utilizados como grupo-controle. Avaliações artroscópica e radiológica do membro posterior esquerdo foram realizadas antes da secção do ligamento, no dia da sua substituição e 90 dias após a cirurgia. Histologicamente, o efeito da associação de hialuronato de sódio e sulfato de condroitina foi mais evidente na membrana sinovial, observando-se regeneração da camada íntima e diminuição da infiltração linfoplasmocitária na sub-íntima. Artroscópica e macroscopicamente não houve prevenção das lesões cartilaginosas decorrentes da DAD.

The aim of this study was the assessment of hyaluronic acid and chondroitin sulphate association in the therapy of degenerative joint disease (DJD) in dogs. Ten mongrel dogs underwent arthroscopic section of cruciate cranial ligament aiming the development of DJD. Twenty one days after the procedure, surgical substitution of cruciate cranial ligament was carried out in all animals. Then five animals were treated with the combination of hyaluronic acid and chondroitin sulphate. The other five dogs were used as controls. Arthroscopical and radiological evaluations of the left fore limb were carried out before arthroscopic section at the some day and 90 days after cruciate cranial ligament substitution. Histologically the effect of the association of hyaluronic acid and chondroitin sulphate was more evident in the synovial membrane that had regeneration of the intimal layer and reduced lympho-plasmocitic infiltrate in the sub-intimal layer. However, the treatment did not prevent DJD cartilage lesions evaluated by arthroscopy and radiology.

Human plasma kallikrein, a serine proteinase, plays a key role in intrinsic blood clotting, in the kallikrein-kinin system, and in fibrinolysis. The proteolytic enzymes involved in these processes are usually controlled by specific inhibitors and may be influenced by several factors including glycosaminoglycans, as recently demonstrated by our group. The aim of the present study was to investigate the effect of glycosaminoglycans (30 to 250 µg/ml) on kallikrein activity on plasminogen and factor XII and on the inhibition of kallikrein by the plasma proteins C1-inhibitor and antithrombin. Almost all available glycosaminoglycans (heparin, heparan sulfate, bovine and tuna dermatan sulfate, chondroitin 4- and 6-sulfates) reduced (1.2 to 3.0 times) the catalytic efficiency of kallikrein (in a nanomolar range) on the hydrolysis of plasminogen (0.3 to 1.8 µM) and increased (1.9 to 7.7 times) the enzyme efficiency in factor XII (0.1 to 10 µM) activation. On the other hand, heparin, heparan sulfate, and bovine and tuna dermatan sulfate improved (1.2 to 3.4 times) kallikrein inhibition by antithrombin (1.4 µM), while chondroitin 4- and 6-sulfates reduced it (1.3 times). Heparin and heparan sulfate increased (1.4 times) the enzyme inhibition by the C1-inhibitor (150 nM).

Apoptosis and necrosis are two distinct forms of cell death that can occur in response to different agents and stress conditions. In order to verify if the oxidative stress induced by dietary selenium and vitamin E deficiencies can lead muscle cells to apoptosis, one-day-old chicks were reared using diets differing in their vitamin E (0 or 10 IU/kg) and selenium (0 or 0.15 ppm) supplementation. Chick skeletal muscle tissue was obtained from 28-day-old animals and used to verify apoptosis occurrence based on caspase activity detection and DNA fragmentation. Antioxidant deficiency significantly increased caspase-like activity assessed by the hydrolysis of fluorogenic peptide substrates (Abz-peptidyl-EDDnp) at lambdaexc = 320 nm and lambdaem = 420 nm. Proteolytic activation was not accompanied by typical internucleosomal DNA fragmentation detected by field inversion gel electrophoresis. Although the general caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp(O-Me) fluoromethyl ketone (Z-VAD-fmk) (0 to 80 muM) did not block caspase-like activity when preincubated for 30 min with muscle homogenates, the hydrolyzed substrates presented the same cleavage profile in HPLC (at the aspartic acid residue) when incubated with the purified recombinant enzyme caspase-3. These data indicate that oxidative stress causes caspase-like activation in muscle cells and suggest that cell death associated with exudative diathesis (dietary deficiency of selenium and vitamin E) can follow the apoptotic pathway.

Foram estudadas as alterações cutâneas de ratas Wistar adultas castradas e não castradas, mantidas em estado hipotireóideo por 120 dias. Dois grupos eutireóideos, um castrado e outro não castrado, serviram de controle. Secções da pele abdominal ventral e torácica dorsal foram coradas pelas técnicas de HE, PAS, azul de alcian (alcian blue), picro-sirius red-luz polarizada e Verhoeff. Adelgaçamento da epiderme, atrofia de glândulas sebáceas, redução parcial ou total de fibras elásticas e do colágeno do tipo III da derme caracterizaram tanto o hipotireoidismo quanto a castração. Retardo no crescimento dos folículos pilosos e hiperceratose foram vistos apenas na deficiência dos hormônios tireoidianos, independente do estado funcional das gônadas. A associação hipotireoidismo e castração caracterizou-se por adelgaçamento da epiderme da região abdominal ventral e espessamento e aumento da celularidade na região torácica dorsal, com derme adelgaçada e desprovida de fibras elásticas e de colágeno do tipo III. Conclui-se que a deficiência dos hormônios sexuais ou tireoidianos altera todos os componentes da pele e que as lesões são agravadas na associação hipotireoidismo-castração.

The cutaneous alterations of castrated and intact female Wistar rats kept under a hypothyroidism state for 120 days were studied. Two euthyroid groups, one castrated and other intact, served as controls. Ventral abdominal and dorsal thoracic skin sections were stained by HE, PAS, alcian blue, picro-sirius red-polarized light and Verhoeff. Epidermis and sebaceous glands atrophy, partial or total reduction of elastic fibrils and type III dermal collagen were observed in both hypothyroidism and castration. Delay in hair follicle growth and hyperkeratosis were only observed when deficiency of thyroid hormones was present, independent of gonadal function. The association of hypothyroidism and castration was characterized by ventral abdominal epidermis atrophy, thickening and hyperplasia of dorsal thoracic epidermis, dermis atrophy with loss of elastic fibrils and type III collagen. In conclusion, ovarian steroids or thyroid hormones deficiency modifies all the components of the skin and that the injuries are aggravated in the association hypothyroidism-castration.

The goal of this study was to determine whether the quantification of the nucleolar organizer regions (AgNORs) is a useful parameter for evaluation of the proliferative potential of non-neoplastic granulosa cells in ovarian follicles at different stages of development. Seven ovaries from six-month-old rats, all of which in metestrus-diestrus, were studied. The number of AgNORs from 60 granulosa cell nuclei was quantified in secondary follicles with two to three layers of cells and in follicles with more than five layers of granulosa cells. Follicles with two to three layers had larger AgNORs in lower numbers, whereas more developed secondary follicles the AgNORs were predominantly smaller, scattered throughout the nucleus, and in significantly higher numbers. In conclusion, quantification of the nucleolar organizer regions is an appropriate parameter for differentiation of the proliferative potential of non-neoplastic granulosa cells.

Occurrence of contact pododermatitis in broilers in the State of Minas Gerais, Brazil, is reported. Lesions in the footpad were detected as early as 13 days of age and progressed to ulceration. Histologically, primarily inflammatory and degenerative changes mostly at the epidermal-dermal junction were observed. Retrospective evaluation indicated that pododermatitis in these cases were associated with exposure to high litter moisture during the first days of life.

Foram investigadas a morfologia e a função tireoidiana de ratas Wistar, adultas, castradas e não castradas e mantidas em estado hipotireóideo pela administração diária de propiltiouracil por 120 dias. Ratas eutireóideas castradas e não castradas serviram de controle. As tireóides, colhidas ao final do experimento, foram pesadas, processadas histologicamente e submetidas à análise morfométrica, pela qual foi determinada a proporção dos componentes glandulares (epitélio folicular, colóide e estroma). No plasma sangüíneo, colhido também ao final do período experimental, foram determinadas as concentrações de T3 total, T4 livre e TSH. O peso e a histomorfometria da tireóide não sofreu influência da castração e o aumento do componente epitelial e decréscimo da quantidade de colóide só foram detectados no hipotireoidismo. No estado eutireóideo a deficiência dos esteróides sexuais levou ao aumento dos valores de T4 livre e T3 total e no hipotireoidismo, exacerbou a queda de T3 total, mas não a de T4 livre. Os valores de TSH não se alteraram em nenhum dos estados funcionais da glândula ou das gônadas. Conclui-se que o hipogonadismo não modifica a hiperplasia glandular e a queda dos níveis plasmáticos de tiroxina livre induzidos pelo propiltiouracil, mas altera profundamente o comportamento da triiodotironina total de acordo com o estado funcional da tireóide, tudo sem alterar os valores plasmáticos de TSH.

The morphology and function of the thyroids of female adult Wistar rats were investigated. The animals were either castrated or intact and kept in a hypothyroid condition by a treatment with propylthiouracil for 120 days. Castrated and intact euthyroid rats were used as controls. The thyroids were collected at the end of the experiment, weighted, histologically processed, and morphometrically evaluated. Proportions of each glandular component, namely, follicular epithelium, colloid, and stroma, were determined. Serum concentrations of total T3, free T4, and TSH were assessed at the end of the experimental period. The weight and the morphometric parameters were not influenced by castration, whereas an increase in the epithelial component associated with a decreased amount of colloid were observed only in hypothyroid animals. Under an euthyroid state, the deficiency of sexual hormones induced an increase in the levels of free T4 and total T3. In hypothyroid animals, withdrawal of sexual hormones caused an exacerbation of the decrease in total T3, but not in free T4. TSH levels were not affected by the thyroid or the functional condition of gonads. In conclusion, hypogonadism did not influence the glandular hyperplasia and decrease in plasmatic levels of free thyroxin induced by propylthiouracil, but markedly changed the profile of total T3 according to the functional condition of the thyroid, in the absence of changes in the plasmatic levels of TSH.

The influence of the estrous cycle on the thyroid gland was studied. Twenty one five-to-seven-month-old Wistar female rats were divided according to the stage of the estrous cycle in two groups: metaestrus-diestrus and proestrus-estrus. After gross inspection, the thyroids were weighed, sampled, and processed for staining with hematoxilyn-eosin. Seric concentrations of total T4, free T4, total T3, TSH, progesterone, and estradiol were measured. The values of estradiol were significantly higher in the proestrus-estrus stage. However, no significant differences in the plasmatic concentrations of progesterone, free T4, total T4 and TSH throughout the cycle were found. The results of the morphometric study of the thyroid did not indicate any significant differences between the groups. These findings suggest that there is no thyreotrophic effect of estrogen during the estrous cycle in rats.

Foi testada a habilidade da toxina T-2, produzida por Fusarium sporotrichioides Sherb e veiculada por milho experimentalmente contaminado, em induzir alterações da placa epifisária proximal do tibiotarso de frangos de corte. Pintos de um dia, todos machos e da linhagem Hubbard, foram alimentados com ração básica a base de milho e soja, na qual todo o milho foi substituído por milho contaminado, contendo exclusivamente T-2 na quantidade de 2,64mg/kg. Um outro grupo alimentado com milho não contaminado serviu como testemunha e ambos foram observados por três períodos (7, 14 e 21 dias). Independente do período e da quantidade de T-2 ingerida (0,3 a 1,9 mg/kg), o tibiotarso dos animais tratados mostrou maturação e diferenciação defectivas de condrócitos, lesões vasculares e penetração vascular da cartilagem, todas similares às da discondroplasia tibial. Conclui-se que a toxina T-2 oriunda de Fusarium sporotrichioides Sherb é capaz de induzir lesões básicas e iniciais da discondroplasia tibial em frangos de corte.

The ability of T-2 toxin from Fusarium sporotrichioides Sherb in corn culture to induce epiphyseal plate lesions in broiler chicks was tested. One group of day-old male broiler chickens (Hubbard) fed ad libitum balanced diet in which all corn was replaced by T-2 toxin (2.64mg/kg) contaminated autoclaved corn. Another group received the same diet with mycotoxin free corn, and was used as control. All groups were observed for 7, 14 and 21 days. Despite the different periods and amounts of ingested T-2 (estimated in 0.3 to 1.9 mg/kg), the tibia of treated animals presented defective maturation and poor differentiation of chondrocytes, severe vascular lesions and anomalous cartilage vascular invasion and retarded cartilage erosion with a picture similar to that of early tibial dyschondroplasia. The results indicated that the T-2 toxin produced by Fusarium sporotrichioides Sherb could induce tibial dyschondroplasia in broiler chickens.