Selective inhibition of interleukin 6 receptor decreased inflammatory cytokines and increased proteases in an experimental model of critical calvarial defect.

Considering the lack of consensus related to the impact of selective IL-6 receptor inhibition on bone remodeling and the scarcity of reports, especially on large bone defects, this study proposed to evaluate the biological impact of the selective inhibitor of interleukin-6 receptor (tocilizumab) in an experimental model of critical calvarial defect in rats. In this preclinical and in vivo study, 24 male Wistar rats were randomly divided into two groups (n=12/group): defect treated with collagen sponge (CG) and defect treated with collagen sponge associated with 2 mg/kg tocilizumab (TCZ). The defect in the parietal bone was created using an 8-mm diameter trephine drill. After 90 days, the animals were euthanized, and tissue samples (skull caps) were evaluated through micro-CT, histological, immunohistochemistry, cytokines, and RT-qPCR analyses. Tocilizumab reduced mononuclear inflammatory infiltration (P<0.05) and tumor necrosis factor (TNF)-α levels (P<0.01) and down-regulated tissue gene expression of BMP-2 (P<0.001), RUNX-2 (P<0.05), and interleukin (IL)-6 (P<0.05). Moreover, it promoted a stronger immunostaining of cathepsin and RANKL (P<0.05). Micro-CT and histological analyses revealed no impact on general bone formation (P>0.05). The bone cells (osteoblasts, osteoclasts, and osteocytes) in the defect area were similar in both groups (P>0.05). Tocilizumab reduced inflammatory cytokines, decreased osteogenic protein, and increased proteases in a critical bone defect in rats. Ninety days after the local application of tocilizumab in the cranial defect, we did not find a significant formation of bone tissue compared with a collagen sponge.

Selective inhibition of interleukin 6 receptor decreased inflammatory cytokines and increased proteases in an experimental model of critical calvarial defect

Considering the lack of consensus related to the impact of selective IL-6 receptor inhibition on bone remodeling and the scarcity of reports, especially on large bone defects, this study proposed to evaluate the biological impact of the selective inhibitor of interleukin-6 receptor (tocilizumab) in an experimental model of critical calvarial defect in rats. In this preclinical and in vivo study, 24 male Wistar rats were randomly divided into two groups (n=12/group): defect treated with collagen sponge (CG) and defect treated with collagen sponge associated with 2 mg/kg tocilizumab (TCZ). The defect in the parietal bone was created using an 8-mm diameter trephine drill. After 90 days, the animals were euthanized, and tissue samples (skull caps) were evaluated through micro-CT, histological, immunohistochemistry, cytokines, and RT-qPCR analyses. Tocilizumab reduced mononuclear inflammatory infiltration (P<0.05) and tumor necrosis factor (TNF)-α levels (P<0.01) and down-regulated tissue gene expression of BMP-2 (P<0.001), RUNX-2 (P<0.05), and interleukin (IL)-6 (P<0.05). Moreover, it promoted a stronger immunostaining of cathepsin and RANKL (P<0.05). Micro-CT and histological analyses revealed no impact on general bone formation (P>0.05). The bone cells (osteoblasts, osteoclasts, and osteocytes) in the defect area were similar in both groups (P>0.05). Tocilizumab reduced inflammatory cytokines, decreased osteogenic protein, and increased proteases in a critical bone defect in rats. Ninety days after the local application of tocilizumab in the cranial defect, we did not find a significant formation of bone tissue compared with a collagen sponge.

Comparação entre o método de referência e a análise eletrônica na determinação da contagem de células somáticas do leite bovino / Comparison between standard method and electronic analyses for measurement of the bovine milk somatic cell count

Avaliou-se a metodologia eletrônica de determinação da contagem de células somáticas por citometria de fluxo, utilizando-se 48 amostras individuais de leite de vaca da raça Holandesa e cinco amostras de leite de conjunto. A contagem média de células somáticas das amostras individuais foi de 353.000 cel/ml (5,55log cel/ml) usando-se metodologia de referência e 328.000 cel/ml (5,52log cel/ml) usando-se o contador eletrônico. Para amostras de tanque, as médias foram 382.000 cel/ml (5,58log cel/ml) e 329.000 cel/ml (5,52log cel/ml) de CCS, respectivamente, para análise feita por microscopia direta e pelo equipamento eletrônico. Não houve diferença (P>0,05) entre os valores obtidos nas análises realizadas pelo método de referência e pelo analisador eletrônico rápido. Foi avaliada a qualidade das amostras-padrão de origem americana e canadense, por meio da contagem de células somáticas, pelo método de microscopia direta. Os resultados foram comparados aos valores declarados no laudo de análise das amostras, emitidos pelo laboratório fornecedor das amostras-padrão.

Comparação entre os métodos de referência e a análise eletrônica na determinação da composição do leite bovino / Comparison between standard methods and electronic analyses for measurement of the bovine milk composition

Avaliou-se a metodologia de determinação da composição do leite por meio de analisador de infravermelho, utilizando-se 48 amostras individuais de leite de vacas da raça Holandesa e cinco amostras de leite de conjunto. A média dos resultados para gordura, proteína, lactose e sólidos totais das amostras individuais foram, respectivamente, 3,8 por cento, 3,3 por cento, 4,6 por cento e 12,4 por cento, usando-se metodologia de referência e 3,8 por cento, 3,3 por cento, 4,5 por cento e 12,4 por cento, usando-se equipamento eletrônico. Para amostras de tanque, as médias foram 3,9 por cento e 4,0 por cento para gordura, 3,2 por cento e 3,2 por cento para proteína, 4,7 por cento e 4,6 por cento para lactose e 12,6 por cento e 12,6 por cento para sólidos totais, respectivamente, para análises feitas por métodos de referência e por analisador de infravermelho. Não houve diferença (P>0,05) entre os valores das duas análises. Foi avaliada a qualidade das amostras-padrão canadense e americano, determinando-se os teores de gordura, proteína, lactose e sólidos totais por métodos de referência. Os resultados foram comparados com os valores declarados no laudo de análise das amostras, emitidos pelo laboratório fornecedor.