Abstract Lipoproteins are important bacterial immunostimulating molecules capable of inducing receptor activator of nuclear factor-κB (RANKL) and osteoclast formation in vitro and in vivo . Although these molecules are present in periodontopathogenic bacteria, their role in periodontitis is not known. In this study, we used Pam2CSK4 (PAM2), a synthetic molecule that mimics bacterial lipoprotein, to investigate the effects of lipoproteins on periodontitis in mice. C57BL/6 male mice were randomly divided into three experimental groups: 1) Negative control group: animals received vehicle injection; 2) Positive control group: animals received injection of Escherichia coli lipopolysaccharide (LPS); 3) PAM2 group: animals received PAM2 injection. All the injections were performed bilaterally every other day into the palatal mucosa between first and second molars. After twenty-four days, the animals were euthanized to assess alveolar bone volume (micro-CT), cellular and extracellular composition in the gingiva (stereometric analysis), and osteoclast numbers (TRAP staining). Treatment with either PAM2 or LPS induced gingival inflammation, as demonstrated by increased infiltration of inflammatory cells and enhanced angiogenesis, associated with a smaller number of fibroblasts and decreased extracellular matrix. Importantly, treatment not only with LPS but also with PAM2 resulted in a larger number of TRAP+ multinucleated osteoclasts and significant loss of alveolar bone. Collectively, our data demonstrate that PAM2 can induce gingival inflammation and bone loss in mice, broadening the avenues of investigation into the role of lipoproteins in the pathogenesis of periodontal disease.

Abstract Objective: Several studies reported the local tissue reaction caused by mineral aggregate-based cements. However, few studies have investigated the systemic effects promoted by these cements on liver and kidney when directly applied to connective tissue. The purpose of this in vivo study was to investigate the systemic effect of mineral aggregate-based cements on the livers and kidneys of rats. Material and Methods: Samples of Mineral Trioxide Aggregate (MTA) and a calcium aluminate-based cement (EndoBinder) containing different radiopacifiers were implanted into the dorsum of 40 rats. After 7 and 30 d, samples of subcutaneous, liver and kidney tissues were submitted to histopathological analysis. A score (0-3) was used to grade the inflammatory reaction. Blood samples were collected to evaluate changes in hepatic and renal functions of animals. Results: The moderate inflammatory reaction (2) observed for 7 d in the subcutaneous tissue decreased with time for all cements. The thickness of inflammatory capsules also presented a significant decrease with time (P<.05). Systemically, all cements caused adverse inflammatory reactions in the liver and kidney, being more evident for MTA, persisting until the end of the analysis. Liver functions increased significantly for MTA during 30 d (P<.05). Conclusion: The different cements induced to a locally limited inflammatory reaction. However, from the systemic point of view, the cements promoted significant inflammatory reactions in the liver and kidney. For MTA, the reactions were more accentuated.

Abstract This study aimed to characterize the dynamics of suppressor of cytokine signaling (SOCS1) expression in a rat model of lipopolysaccharide-induced periodontitis. Wistar rats in the experimental groups were injected three times/week with LPS from Escherichia coli on the palatal aspect of the first molars, and control animals were injected with vehicle (phosphate-buffered saline). Animals were sacrificed 7, 15, and 30 days after the first injection to analyze inflammation (stereometric analysis), bone loss (macroscopic analysis), gene expression (qRT-PCR), and protein expression/activation (Western blotting). The severity of inflammation and bone loss associated with LPS-induced periodontitis increased from day 7 to day 15, and it was sustained through day 30. Significant (p < 0.05) increases in SOCS1, RANKL, OPG, and IFN-γ gene expression were observed in the experimental group versus the control group at day 15. SOCS1 protein expression and STAT1 and NF-κB activation were increased throughout the 30-day experimental period. Gingival tissues affected by experimental periodontitis express SOCS1, indicating that this protein may potentially downregulate signaling events involved in inflammatory reactions and bone loss and thus may play a relevant role in the development and progression of periodontal disease.

OBJETIVO: Determinar os efeitos da administração oral de L-glutamina (L-Gln) e do dipeptídeo L-alanil-glutamina (L-Ala-Gln) sobre a atividade do ciclo malato-aspartato no intestino delgado distal de ratos após isquemia/reperfusão. MÉTODOS: Setenta e dois ratos Wistar (350-400g) foram randomizados em 2 grupos (n = 36): T grupo S (Sham) e grupo (Tratamento) e distribuídos em 12 subgrupos (n = 6): A-A6, e B1-B6. Os subgrupos A1-A3 foram submetidos a procedimentos "sham" aos 30 e 60 minutos. Trinta minutos antes do estudo, os ratos foram tratados com caseinato de cálcio, 0,5 g/kg (subgrupos A1, A4, B1 e B4), L-Gln, 0,5 g/kg (subgrupos A2, A5, B2 e B5) ou L-Ala -Gln, 0,75g/kg (subgrupos A3, A6, B3, B6), administrado por gavagem. A isquemia foi obtida por pinçamento dos vasos mesentéricos, delimitando um segmento do intestino cinco centímetros de comprimento e 5 cm da válvula ileocecal. Amostras foram coletadas aos 30-60 minutos para ensaio de PCR em tempo real das enzimas malato desidrogenases (MDH1-2), aspartato-aminotransferase (GOT1-2). RESULTADOS: A expressão de MDH e GOT mRNA nas amostras provenientes do intestino delgado de ratos pré-condicionados com L-Gln ou L-Ala-Gln não apresentou diferenças significativas, tanto durante a isquemia como na fase inicial de reperfusão. CONCLUSÃO: Ativação do ciclo malato-aspartato não parece ser o mecanismo de elevação glutamina-mediada da oxidação da glicose no intestino de ratos durante a isquemia / reperfusão.

PURPOSE: To determine the effects of oral L-glutamine (L-Gln) and the dipeptide l-alanyl-glutamine (L-Ala-Gln) upon the activity of the malate-aspartate shuttle in the rat distal small intestine following ischemia and reperfusion. METHODS: Seventy-two Wistar rats (350-400g), were randomized in 2 groups (n = 36): group S (Sham) and Group T (Treatment) and divided into 12 subgroups (n = 6): A-A6, and B1-B6. The subgroups A1-A3 were subjected to sham procedures at 30 and 60 minutes. Thirty minutes before the study, rats were treated with calcium caseinate, 0.5g/Kg (subgroups A1, A4, B1, B4), L-Gln, 0.5g / kg (subgroups A2, A5, B2 and B5) or L-Ala-Gln, 0.75g/Kg (subgroups A3, A6, B3, B6), administered by gavage. Ischemia was achieved by clamping the mesenteric vessels, delimiting a segment of bowel 5 cm long and 5 cm apart from the ileocecal valve. Samples were collected 30 and 60 minutes after start of the study for real-time PCR assay of malate dehydrogenases (MDH1-2) and aspartate-aminotransferases (GOT1-2) enzymes. RESULTS: Tissue MDH and GOT mRNA expression in intestinal samples from rats preconditioned with either L-Gln or L-Ala-Gln showed no significant differences both during ischemia and early reperfusion. CONCLUSION: Activation of the malate-aspartate shuttle system appears not to be the mechanism of glutamine-mediated elevation of glucose oxidation in rat intestine during ischemia/reperfusion injury.