白藜芦醇对实验性兔骨关节炎软骨细胞凋亡及bcl-2 bax表达的影响

Effect of resveratrol on apoptosis and expression of bal-2 and bax protein in articular chondrocytes of experhnental osteoarthritis model

目的研究白藜芦醇对兔实验性骨关节炎（0A）软骨细胞凋亡及凋亡调控基因bcl-2、bax表达的影响，探讨其治疗OA的机制。方法30只新西兰大白兔随机平分为5组，A组（健康对照组）、B组（模型对照组）、C组（白藜芦醇高剂量干预组）、D组（白藜芦醇中剂量干预组）、E组（白藜芦醇低剂量干预组）。除A组外，其他各组均以Hulth法复制膝OA模型。术后第4周开始，A组、B组每天以5ml含0．1％二甲基亚砜的蒸馏水灌胃；白藜芦醇干预各组每天以相应剂量白藜芦醇溶液（浓度为60mg／m1）灌胃，C、D、E组日剂量分别为120、60、30mg·kg^-1·d^-1，连续6周。第10周处死大白兔，取右膝关节股骨内髁内侧软骨，软骨组织切片用脱氧核糖核苷酸末端转移酶介导的缺口末端标记（TUNEL）法观察软骨细胞凋亡，免疫组织化学法观察软骨细胞bcl-2和bax的表达。结果①模型对照组关节软骨细胞凋亡率明显高于健康对照组；白藜芦醇干预各组可不同程度地降低OA软骨细胞凋亡率，差异有统计学意义（P〈0．05），且呈剂量依赖性。②与健康对照组相比，模型对照组关节软骨细胞bcl-2和bax阳性率均升高（P〈0．01），bcl-2／bax的比值降低；白藜芦醇干预后，bcl-2阳性率升高更为明显（P〈0．01）；而bax阳性率有不同程度降低（P〈0．01）；bcl-2／bax的比值均不同程度提高（P〈0．01）。结论白藜芦醇通过上调bcl-2的表达，下调bax的表达，提高bcl-2／bax的比值，以抑制兔实验性OA中软骨细胞的过度凋亡，达到保护软骨，防治OA的目的。

Objective To observe the effect of resveratrol on the apoptosis and expressions of bal-2 and bax protein in articular chondrocytes of rabbits experimental osteoarthritis （OA） model, and further explore the mechanisms of resveratrol in the treatment of OA. Methods Thirty Newzealand rabbits were randomly divided into 5 groups： group A （normal control group）, group B （model control group）, group C （resveratrol intervention high dosage group）, group D（resveratrol intervention middle dosage group）, group E （resveratrol intervention low dosage group）. The model of OA was established with Huhh＇s modeling method in group B, C, D, E. Four weeks later , groups A and B received intragastric administration of distilled water containing 0.1% DMSO daily and group C, D, E received intragastric administration of resveratrol solution daily （concentration was 60 mg/ml） in different dosages for 6 weeks. Daily dosages of group C, D, E were 120, 60, 30 mg ·kg^-1·d^-1, respectively. Then the rabbits were sacrificed and the cartilage sections of right femoral medial condyle were analyzed by immunohistochemistry for bcl-2 and hax, TUNEL for apoptosis. Results ① The apoptosis rates of chondrocytes in group B, C, D, E were significantly higher than those in group A （P〈0.01）. The apoptosis rates of chondrocytes in group C, D, E were decreased compared with those in group B （P〈0.05）. ② The positive rates of bcl-2 and bax expression in chondrocytes in group B were significantly higher than those in group A （P〈0.01）, but the ratio of the positive rate of bcl-2 expression to that of bax in group B was lower than that in group A （P〈0.01）. The positive rates of bcl-2 expression in chondrocytes in group C, D, E were much higher compared with those in group B （P〈0.01）. The positive rates of bax expression in chondrocytes in group C,D,E were lower compared with those in group B （P〈0.01）. The ratio of the positive rate of bcl-2 expression to that of bax was increased in group C, D, E compared with group B （P〈0.01）. Conclusion Resveratrol can suppress the excessive apoptosis of chondrocytes in experimental OA by up-regulating the expression of bcl-2 while down-regulating the expression of bax and improving the ratio of bcl-2 to bax . Suppressing the excessive apoptosis of chondrocytes in experimental OA may be one of the mechanisms for resveratrol＇s effect in the treatment of osteoarthritis.