Grape seed extract inhibits apoptosis in growth plate chondrocytes and promotes tibial growth in rats / 中国组织工程研究

ABSTRACT

BACKGROUND:Grape seed extract has been shown to be effective in inhibiting the growth of androgen-dependent tumors(e.g.,breast cancer),and thus grape seed extract could theoretically inhibit epiphyseal closure induced by estrogen in late adolescence. OBJECTIVE:To screen the effects of grape seed extract on apoptosis of growth plate chondrocytes and epiphyseal closure in rats. METHODS:(1)In vitro experimentGrowth plate chondrocytes from rat large tibia and femur at logarithmic growth stage were obtained and cultured in groupsnormal control group,model control group(adding 17β-estradiol to induce apoptosis),positive control group(adding letrozole and 17β-estradiol),grape seed extract group(adding 17β-estradiol and 10 μg/mL grape seed extract),Caspase-9 inhibitor group(adding 17β-estradiol and Caspase-9 inhibitor),Caspase-9 agonist group(adding 17β-estradiol and Caspase-9 agonist).Cell apoptosis was detected by flow cytometry after 48 hours of culture.(2)In vivo experimentThirty 3-month-old Sprague-Dawley rats were randomly divided into model control group,positive control group and low-,medium-and high-dose groups,with five rats in each group.All rats were injected subcutaneously with 17β-estradiol(3 times per week)to establish epiphyseal closure models,followed by intragastric administration of letrozole in positive control group and 0.05,0.2 and 0.8 g/kg grape seed extract in low-,medium-and high-dose groups,respectively,once a day until over 2/3 of the epiphyseal plate in the model control group was closed.The length of the tibia was then observed.Another 18 Sprague-Dawley rats were randomly divided into model control group,positive control group,and medium-dose group,with 6 rats in each group,treated as above for 1.5 continuous months.The expression of Caspase-9 protein in rat growth plate cartilage was detected by western blot. RESULTS AND CONCLUSION:(1)In vitro experiment17β-estradiol could induce apoptosis in growth plate chondrocytes,and letrozole,grape seed extract,and caspase-9 inhibitors could all inhibit apoptosis in growth plate chondrocytes.(2)In vivo experimentWhen more than 2/3 of the epiphyseal plate in the model control group was closed,the number of rats with epiphysis closure in the positive control and medium-dose groups was less than that in the model control group(P＜0.05),and the tibial length was longer than that in the model control group(P＜0.05),and the Caspase-9 protein expression in the tibial growth plate was lower than that in the model control group(P＜0.05).To conclude,the appropriate dose of grape seed extract can effectively inhibit the apoptosis of growth plate chondrocytes and delay epiphyseal closure,which has the potential to promote bone growth.