Abstract Objective This study aimed to evaluate the inflammatory effect and bone formation in sterile surgical failures after implantation of a collagen sponge with mesenchymal stem cells from human dental pulp (hDPSCs) and Aloe vera. Material and Methods Rattus norvegicus (n=75) were divided into five experimental groups according to treatment: G1) control (blood clot); G2) Hemospon®; G3) Hemospon® in a culture medium enriched with 8% Aloe vera; G4) Hemospon® in a culture medium containing hDPSCs and G5) Hemospon® in a culture medium enriched with 8% Aloe vera and hDPSCs. On days 7, 15 and 30, the animals were euthanized, and the tibia was dissected for histological, immunohistochemistry and immunofluorescence analyses. The results were analyzed using nonparametric Kruskal-Wallis test and Dunn’s post-test. Results On days 7 and 15, the groups with Aloe vera had less average acute inflammatory infiltrate compared to the control group and the group with Hemospon® (p<0.05). No statistically significant difference was found between the groups regarding bone formation at the three experimental points in time. Osteopontin expression corroborated the intensity of bone formation. Fluorescence microscopy revealed positive labeling with Q-Tracker® in hDPSCs before transplantation and tissue repair. Conclusion The results suggest that the combination of Hemospon®, Aloe vera and hDPSCs is a form of clinical treatment for the repair of non-critical bone defects that reduces the inflammatory cascade’s effects.

The incorporation of zinc onto biomaterials may improve their biological properties, since it is an essential trace element, involved on important steps of bone remodeling. The aim of this work was to evaluate the in vivo biocompatibility of previously characterized hydroxyapatite granules incorporated with 5% zinc (ZnHA), through a subcutaneous grafting test. Granules produced from powders of ZnHA or stoichiometric HA were subcutaneously grafted onto Balb/c mice, and histomorphometrical analysis was performed at 7, 14, 21, 28 or 60 days after grafting. HA and ZnHA induced a similar foreign body reaction, with formation of granulome and the presence of a fibrous capsule. Granulocytes were virtually absent, and agranulocytes decreased with time. ZnHA treated samples presented faster reduction on multinucleated giant cells and increase on observed angiogenesis, as compared to HA. It could be concluded that ZnHA granules are biocompatible. Further study should better address its potential use for bone therapy.

INTRODUÇÃO E OBJETIVO: O efeito da tibolona utilizada em alta dose e por tempo prolongado foi analisado mediante estudo histomorfométrico de tíbias e fêmures de ratas castradas. MÉTODOS: O experimento utilizou 20 ratas Wistar, com peso médio de 250 g. Os animais foram distribuídos aleatoriamente em três grupos: ooforectomizado recebendo tibolona (OVX + T) (n = 9), ooforectomizado (OVX) (n = 6) e grupo controle não ooforectomizado (C) (n = 5). Deu-se início ao protocolo experimental 30 dias após a ooforectomia, perdurando por 20 semanas, com administração de tibolona (1 mg/dia) a OVX + T e carboximetilcelulose a OVX. O grupo C não foi submetido a qualquer tratamento. Tíbias e fêmures direitos foram fixados em formol a 10% tamponado, descalcificados e processados para inclusão em parafina. Os cortes histológicos foram corados mediante hematoxilina-eosina para análise histomorfométrica. Mediram-se a espessura cortical e a cavidade medular em cortes transversais de tíbia e fêmur e percentual de porosidade e densidade trabecular em cortes longitudinais de fêmur. RESULTADO E DISCUSSÃO: Não houve diferença estatística entre OVX e OVX + T nas diversas análises. Os resultados demonstram que a tibolona não melhorou de forma significativa a qualidade óssea, porém preservou a massa óssea cortical, nas diáfises femoral e tibial, e o osso trabecular, nos côndilos femorais. O uso prolongado de tibolona em concomitância com alta dose pode ter influenciado tais efeitos, já que estudos recentes têm preconizado a utilização de doses mais baixas na prevenção da osteoporose. CONCLUSÃO: A ooforectomia ocasionou perda óssea nas regiões analisadas; a tibolona, apesar de não ter aumentado a massa óssea, manteve-a em níveis satisfatórios.

INTRODUCTION AND OBJECTIVE: The effect of tibolone administered in high dose over a prolonged period was analyzed through histomorphometry of tibia and femur samples from castrated rats. METHODS: The experiment was performed in 20 Wistar rats with average weight of 250 g. The animals were randomly divided into three groups: oophorectomized receiving tibolone (OVX + T) (n = 9), oophorectomized (OVX) (n = 6) and non-oophorectomized as control group (C) (n = 5). The experimental protocol was initiated 30 days after oophorectomy and lasted 20 weeks. Tibolone (1 mg/day) was administered to OVX + T rats and carboxymethyl cellulose to OVX. C rats did not go through any treatment. Right side tibias and femurs were fixed in 10% buffered formalin, decalcified and embedded in paraffin. Histological sections were stained by hematoxylin-eosin for histomorphometric analysis. The cortical thickness and medullary cavity were measured in transverse tibia and femur sections. The percentage of porosity and the trabecular density were determined in longitudinal femur sections. RESULTS AND DISCUSSION: There was no significant statistical difference between OVX and OVX + T in several analyses. The results showed that tibolone did not improve bone quality significantly, although it preserved cortical bone mass in femoral and tibial diaphyses and the trabecular bone in femoral condyles. The administration of tibolone in high dose for a prolonged period may have influenced these effects inasmuch as recent studies have recommended the use of lower doses in osteoporosis prevention. CONCLUSION: Oophorectomy caused bone loss in the analyzed regions. Despite the fact tibolone did not augment bone mass, this was kept at satisfactory levels.

The objective of the present study was to evaluate the quality and intensity of the tissue response to two synthetic hydroxyapatites implanted in critical defects in the skulls of rats. Sixty animals were divided into three experimental groups: I (control), II (HA-1 = HA with 28% crystallinity) and III (HA-2 = HA with 70% crystallinity). They were sacrificed 1, 3, 6, and 9 months after implantation (n = 5 individuals per group/period). Histomorphometric analysis included i) counting of polymorphonuclear leucocytes, mast cells, macrophages and foreign body multinucleated giant cells stained with anti-lysozyme; ii) microvascular density stained with anti-Factor VIII and iii) degree of cell proliferation stained with anti-PCNA. There were no significant differences between the experimental groups in either the quality or quantity of cells in the inflammatory infiltrate, or the degree of angiogenesis and cell proliferation. We conclude that HA-1 and HA-2 are biocompatible and that the physico-chemical differences of these biomaterials did not affect cellular response.