Nonlinear effects of caffeine on the viability, synthesis and gene expression of chondrocytes from the offspring of rats treated during pregnancy.

OBJECTIVE: Evaluate the effects of doses of caffeine administered to pregnant rats on the articular cartilage chondrocytes of their offspring. METHODS: Twenty-four adult Wistar rats were randomly assigned to four groups, with one control group and three groups being treated with caffeine at doses of 25, 50 and 100 mg/kg throughout pregnancy. At birth, three offspring/females were euthanized so that the chondrocytes could be extracted. At 7, 14 and 21 days of culture, the chondrocytes were subjected to the MTT cell viability assay and an evaluation of their alkaline phosphatase activity and collagen synthesis. Chondrocytes were also stained by Hematoxylin-eosin, PAS, Safranin-O and Alcian Blue. The Sox-9, Runx-2, aggrecan, collagen-II and alkaline phosphatase gene transcript levels were also evaluated. Mean comparisons were performed by the Student-Newman-Keuls test. RESULTS: Chondrocyte cultures from the 25 mg/kg group had the lowest results, as chondrocytes from this group had reduced viability, percentage of cells, alkaline phosphatase activity and collagen and chondrogenic matrix synthesis. A reduced expression of Sox-9, alkaline phosphatase and collagen-II was also detected in the 25 mg/kg group. Chondrocyte cultures of the group treated with 50 mg/kg caffeine showed reduced collagen synthesis and Sox-9 expression. The caffeine dose of 100 mg/kg also reduced collagen and Sox-9 and alkaline phosphatase expression. CONCLUSION: Caffeine administered to pregnant rats negatively alters the articular cartilage chondrocytes of their offspring, reducing the synthesis of collagen and Sox-9 expression regardless of the dose. This study also concluded that the effects of caffeine are not linear or dose-dependent.

Glicemia de gatos obesos obtida por meio do teste de tolerância à glicose / Glucose of obese cats obtained through the glucose tolerance test

Esse trabalho avaliou a glicemia de gatos obesos por meio do teste de tolerância à glicose, a fim de identificar a hiperglicemia por resistência à insulina nesses animais. Foram avaliados 16 gatos, sendo oito com condição corpórea ideal (Grupo Controle) e oito com sobrepeso (Grupo Sobrepeso). Após jejum alimentar de 12 horas, os animais receberam glicose, via intravenosa, na dose de 0,5g/kg e amostras de sangue foram coletadas para aferição da glicemia no Tempo zero, após 10 (Tempo 1), 30 (Tempo 2), 60 (Tempo 3), 90 (Tempo 4) e 120 (Tempo 5) minutos. No teste de tolerância à glicose, não houve diferença significativa na comparação da glicemia entre os tempos dos dois grupos. Na comparação entre os tempos de um mesmo grupo pode-se verificar que diferentemente do Grupo Controle, não houve diferença significativa entre os Tempo 1 e Tempo 2 do Grupo Sobrepeso, sugerindo um discreto retardo na redução da concentração de glicose entre esses tempos. No estudo realizado, o teste de tolerância à glicose intravenosa apresentou-se factível, porém o período mínimo de 2 anos de obesidade foi insuficiente para a observação de alterações significativas no metabolismo da glicose em gatos obesos. Entretanto, foi possível observar o retardo na redução da concentração de glicose entre 10 e 30 minutos, o que pode estar relacionado à resistência à insulina.