ABSTRACT
OBJETIVO: Avaliar os efeitos in vitro da cafeína na proliferação, apoptose e expressão de transcriptos gênicos de diferenciação condrogênica na cartilagem de crescimento.MÉTODO: As epífises cartilaginosas de fêmures de ratos neonatos foram divididas em dois subgrupos: os tratados com cafeína e o grupo controle, ambos observados nos tempos de 0, 7, 14 e 21 dias. As epífises cartilaginosas de fêmures de cada subgrupo e de cada tempo foram submetidas à histomorfometria, análise imunoistoquímica, técnica de túnel e RT-PCR em tempo real.RESULTADO: A diminuição da atividade proliferativa e o aumento de condroblastos em apoptose aos 21 dias foram encontrados em ambos os subgrupos. Entretanto a diminuição da proliferação celular causada pela cafeína foi menor quando comparada ao grupo controle e aumentou significativamente a expressão de transcriptos gênicos para diferenciação condrogênica, representada pelo SOX-9 e pelo RUNX-2. Entretanto o cultivo in vitro com cafeína demostrou efeitos antagônicos: apesar dos efeitos positivos na proliferação e diferenciação de condroblatos, cafeína aumentou a apoptose, caracterizada pelo aumento da expressão de caspase-3 e do numero de células em apoptose (p< 0.05).CONCLUSÃO: A cafeína apresenta efeitos antagônicos in vitro na cartilagem em crescimento, aumentando a proliferação, diferenciação e apoptose celular. Estudo experimental.
OBJECTIVE: To evaluate the in vitro effetcs of caffeine on proliferation, apoptosis and gene transcripts expression of chondrogenic differentiation in growth cartilage.METHODS: The cartilaginous epiphyses of femurs of newborn rats, which were divided into two subgroups: treated with caffeine and control group, both observed over the time periods of 0, 7, 14 and 21 days. The cartilaginous epiphyses of femurs of each subgroup and each time span were subjected to histomorphometric, immunohistochemical analysis, Tunel technique and RT-PCR in real time.RESULTS: The decrease in proliferative activity and the increase of apoptotic chondroblasts at 21 days were found regardless of the subgroup. However, the decrease in cell proliferation caused by caffeine was lower than in the control group and significantly increased the expression of gene transcripts for chondrogenic differentiation, represented by SOX-9 and RUNX-2. However, the in vitro culture with caffeine revealed antagonistic effects: despite the positive effect on chondroblasts proliferation and differentiation, caffeine increased apoptosis, characterized by increased expression of caspase 3 and of the number of cells undergoing apoptosis (p<0.05).CONCLUSION: Caffeine presents antagonistic effects in vitro on growth cartilage, increasing the proliferation, differentiation and cell apoptosis. Experimental Study.
Subject(s)
Animals , Rats , Apoptosis , Cell Differentiation , Caffeine/biosynthesis , Cartilage/growth & development , Epiphyses/growth & development , Femur , Cell Proliferation , Animals, Newborn , Clinical Trial , Rats, WistarABSTRACT
Methylxanthine contents of maté (Ilex paraguariensis A. St.-Hil.) plants of two varieties (vestita Loes. and paraguariensis) are reported. The plants were cultivated in Ivaí, Paraná, southern Brazil (20º 00' S 50º 50' W), and leaves were gathered in two different harvest times: October, 1998, and February, 2000. Methylxanthine content was found higher in February, 2000, for the two varieties. The var. vestita exhibited lower caffeine contents than the var. paraguariensis in both harvest times. No differences on the theobromine contents between the two varieties were found. The developed HPLC method showed reliable resolution to theobromine, an important feature since we observed some plants with higher theobromine...