慢性睡眠剥夺对大鼠髁突软骨TGF-β1表达的影响

Effect of chronic sleep deprivation on the expression of TGF-β1 in condylar cartilage of rats

目的探讨慢性睡眠剥夺对大鼠髁突内转化生长因子β1(transforming growth factor-β1,TGF-β1)表达的影响。方法将60只Wistar大鼠随机分为3组,分别为实验组、对照组和恢复组。利用改良多平台法(modified multiple platform method,MMPM)对实验组和恢复组大鼠进行慢性睡眠剥夺。通过旷场实验评价大鼠睡眠剥夺模型建立效果。在睡眠剥夺的第1、2、3、4周结束时分别处死实验组和对照组5只大鼠。恢复组大鼠完成1、2、3、4周睡眠剥夺后笼养恢复睡眠1周后处死。大鼠处死后取双侧颞下颌关节。通过HE染色方法观察颞下颌关节髁突的形态学变化,免疫组织化学法检测TGF-β1在髁突软骨内的表达水平的变化。结果通过MMPM成功建立大鼠慢性睡眠剥夺模型,大鼠处于应激状态。HE染色观察到对照组大鼠髁突无明显变化。实验组大鼠髁突表层纤维出现裂隙、断裂、细胞界限不清、软骨下骨向软骨层长入等退行性改变。恢复组大鼠与实验组大鼠相比髁突表层纤维带裂隙减少,局部肥大细胞层数有增加,各层细胞界限较清晰。免疫组织化学结果显示,TGF-β1主要分布于髁突软骨增殖层细胞和纤维软骨层的肥大细胞中。对照组各时间点TGF-β1表达无明显变化,实验组TGF-β1表达随慢性睡眠剥夺时间增长而增加,差异有统计学意义(P<0.05),恢复组TGF-β1表达较实验组有所下降,差异有统计学意义(P<0.05),睡眠剥夺1周恢复组与对照组差异无统计学意义(P>0.05),睡眠剥夺2、3、4周恢复组表达高于对照组,差异有统计学意义(P<0.05)。结论慢性睡眠剥夺可引起大鼠的应激状态,导致髁突软骨发生退行性改变,髁突软骨内TGF-β1表达增加,且随睡眠剥夺时间的增长而增加,睡眠恢复后TGF-β1表达减少。

Objective To study the effect of chronic sleep deprivation(CSD)on the expression of the transforming growth factorβ1(TGF-β1)in condylar cartilage of rats.Methods A total of 60 male Wistar rats were randomly divided into three groups,the experimental group,the control group and the recovery group.The modified multiple platforms method(MMPM)was used to build the CSD of rats in the experimental and recovery group.Open field test was performed to evaluate the effect of sleep deprivation model of rats.At the end of the 1,2,3 and 4 week of sleep deprivation,5 rats in the experimental group and the control group were sacrificed respectively.The rats in recovery group received 1 week of cage feeding after sleep deprivation to recover the sleep,and then were sacrificed.Subsequently,bilateral temporomandibular joints were obtained.HE staining was used to observe morphological changes in the condyle of temporomandibular joint.And the immunohistochemistry was performed to detect the changes of TGF-β1 in condylar cartilage.Results The rat model of CSD was successfully established by the MMPM,and the rat was in a state of stress.HE staining showed no significant change in the condyle of rats in the control group.In the experimental group,there were some degenerative pathological changes like fissures and fractures in the superficial fibers of the condyle of the rats,unclear cell boundaries,and ingrowth of subchondral bone into the cartilage layer.Compared with the rats in the experimental group,the control group showed increased fissures of the fibrous band on the condylar surface of the rats,more layers of local mast cells,and clearer cell boundaries of each layer.The immunohistochemistry showed that the TGF-β1 was mainly expressed in the cells of the proliferative layer of condylar cartilage and mast cells of the fibrocartilage layer.There were no obvious changes in TGF-β1 expression in the control group at different time points,which,however,was increased in the experimental group with the prolonged CSD,suggesting significant differences between two groups(P<0.05).In the recovery group,TGF-β1 expression was slightly decreased compared with the experimental group,and there was significant difference(P<0.05).At 1 week after CSD,no significant difference was found between the recovery group and the control group(P>0.05).However,at 2,3,and 4 weeks after CSD,TGF-β1 expression was higher in the recovery group than in the control group,and the difference was statistically significant(P<0.05).Conclusion CSD can cause stress in rats,leading to degenerative changes in condylar cartilage,and increased TGF-β1 expression in condylar cartilage.TGF-β1 expression increases with prolonged sleep deprivation.In addition,sleep recovery can induce the decrease of TGF-β1 expression.