骨关节炎大鼠膝关节软骨组织中BMAL1、PI3K/AKT信号通路因子表达变化

Expression changes of BMAL1 and PI3K/AKT/mTOR signaling pathway in knee cartilage of osteoarthritis rats

目的观察骨关节炎(OA)大鼠膝关节软骨组织中生物钟基因BMAL1及PI3K/AKT信号通路因子的表达变化,并分析二者的相关性。方法雄性SD大鼠24只,随机分为正常组、模型组、干预组,模型组和干预组采用Hulth法制作OA模型,造模成功后,模型组给予生理盐水灌胃,干预组给予盐酸氨基葡萄糖灌胃;正常组不造模,给予等量生理盐水灌胃。干预28 d后麻醉处死,取关节软骨,采用HE染色及Mankin′s评分评价大鼠OA情况;PCR法检测软骨组织中BMAL1 mRNA和PI3K/AKT信号通路相关因子PI3K、AKT mRNA;Western blotting法检测BMAL1、PI3K、AKT蛋白;分析BMAL1与PI3K、AKT表达的相关性。结果正常组关节软骨具有一定厚度,潮线完整;模型组软骨变薄,潮线不完整,干预组软骨厚度基本正常,潮线基本完整。与正常组比较,模型组、干预组Mankin′s评分均升高(P均<0.01);与模型组比较,干预组Mankin′s评分降低(P均<0.01)。与正常组比较,模型组软骨组织中PI3K、AKT mRNA及蛋白表达升高,BMAL1 mRNA及蛋白表达降低(P均<0.05);与模型组比较,干预组PI3K、AKT mRNA及蛋白表达降低,BMAL1 mRNA及蛋白表达升高(P均<0.05)。BMAL1 mRNA与PI3K、AKT mRNA表达呈负相关(r分别为-0.432、-0.541,P均<0.05);BMAL1蛋白与PI3K、AKT蛋白表达呈负相关(r分别为-0.313、-0.415,P均<0.05)。结论OA大鼠膝关节软骨组织中BMAL1表达下降,PI3K/AKT信号通路被激活,BMAL1与PI3K、AKT基因及蛋白的表达呈负相关。

Objective To observe the expression changes of clock genes BMAL1 and PI3K/AKT/mTOR signaling pathways in knee cartilage of rats with osteoarthritis(OA),and to analyze the correlation between them.Methods Twenty-four male SD rats were divided into three groups:normal group,model group,and intervention group.OA models were made by Hulth method in the model group and intervention group.After successful modeling,the rats in the model group were given normal saline by gavage,and the rats in the intervention group were given glucosamine hydrochloride by gavage.The rats in the normal group were given the same amount of normal saline through intragastric administration.At 28 days after intervention,the rats were anesthetized and sacrificed.The articular cartilage was taken and OA was evaluated by HE staining and Mankin's score.PCR was used to detect BMAL1 mRNA and PI3K/AKT/mTOR signal pathway-related factors PI3K and AKT mRNA in the cartilage tissues;Western blotting was used to detect BMAL1,PI3K and AKT proteins;and the correlation between BMAL1 and PI3K and AKT expression was analyzed.Results In the normal group,articular cartilage had a certain thickness and the tide line was intact.The cartilage of the model group was thinner and the tide line was incomplete,while the cartilage thickness of the intervention group was basically normal and the tide line was basically complete.Compared with the normal group,Mankin's scores in the model group and intervention group increased(both P<0.01).Compared with the model group,the Mankin's score in the intervention group was lower(P<0.01).Compared with the normal group,the mRNA and protein expression levels of PI3K and AKT in the model group increased,while the mRNA and protein expression levels of BMAL1 decreased in the model group(all P<0.05).Compared with the model group,the mRNA and protein expression levels of PI3K and AKT in the intervention group decreased,while the mRNA and protein expression levels of BMAL1 increased(all P<0.05).BMAL1 mRNA was negatively correlated with PI3K and AKT mRNA expression(r=-0.432 and-0.541,respectively;both P<0.05);BMAL1 protein was negatively correlated with PI3K and AKT protein expression(r=-0.313 and-0.415,respectively;both P<0.05).Conclusions The expression of BMAL1 decreased in knee cartilage of OA rats,and PI3K/AKT/mTOR signaling pathway was activated.BMAL1 was negatively correlated with the expression of PI3K,AKT gene and protein.