有氧运动对梗阻性黄疸模型小鼠肝纤维化治疗的机制

Mechanism of aerobic exercise treating liver fibrosis in mouse models of obstructive jaundice

背景:梗阻性黄疸时胆汁淤积造成肝细胞凋亡或坏死致使慢性肝损伤,肝纤维化是机体对其损伤所产生的修复反应,可引发肝功能失调、肝组织硬化等病理改变。目的:分析基因Linc RNA-p21在梗阻性黄疸小鼠肝组织中的表达及生物学功能的关系,并探讨有氧运动干预下LincRNA-p21通过Notch通路对梗阻性黄疸小鼠肝纤维化的改善作用机制。方法:雄性ICR小鼠35只购于湖南斯莱克景达实验动物有限公司,实验过程已获得湖南师范大学医学伦理委员会的同意(伦审科第2018-183号)。所有ICR小鼠采用胆总管悬挂于腹壁构建梗阻性黄疸模型,随机抽取5只建模小鼠剖腹检查验证造模是否成功。剩余30只小鼠随机分成有氧运动组、模型组和对照组。有氧运动组随后进行有氧运动跑台适应性训练,为期1周:第一两天跑台坡度为零,转速为6 m/min,20 min/d;第三四天跑台坡度为5°,转速为8 m/min,40 min/d;第五六天跑台坡度为8°,转速为10 m/min,60 min/d。适应性训练结束后保持坡度为8°,转速为10 m/min的运动强度,60 min/d,6 d/周,直至第7周麻醉后取材,检测各项指标。结果与结论:(1)与对照组比较,模型组血清总胆红素、总胆汁酸、谷丙转氨酶、谷草转氨酶、碱性磷酸酶蛋白浓度显著增高(P <0.01),有氧运动组相比模型组出现不同程度降低(P <0.05,P <0.01);(2)模型组苏木精-伊红染色肝细胞大面积纤维化且肝索排列紊乱,出现空泡、变性及坏死症状;与模型组比较,有氧运动组肝细胞纤维化程度显著降低;(3)与模型组比较,对照组、有氧运动组肝组织LincRNA-p21蛋白及m RNA表达有不同程度升高(P <0.01);对照组高于有氧运动组;Notch-1、Jagged-1、NICD、HES-1蛋白及m RNA表达模型组最高(P <0.01),有氧运动组次之;(4)结果说明,有氧运动干预能促进LincRNA-p21高表达,从而抑制Notch通路参与梗阻性黄疸后小鼠肝纤维化过程,并在一定程度上调节肝损伤后的修复。

BACKGROUND: Hepatocyte apoptosis or necrosis due to cholestasis after obstructive jaundice can induce chronic liver injury. Liver fibrosis is a repairing reaction, which may cause pathological changes, such as liver dysfunction and liver tissue sclerosis. OBJECTIVE: To analyze the relationship between the expression of gene LincRNA-p21 in liver tissue of obstructive jaundice mice and its biological function, and to explore the mechanism of LincRNA-p21 through the Notch pathway improving liver fibrosis in obstructive jaundice mice after aerobic exercise. METHODS: Thirty-five male ICR mice were provided by Hunan Slack Jingda Experimental Animal Co., Ltd., and the study was approved by the Ethics Committee of Hunan Normal University, approval No. 2018-183. All mice were used to construct the obstructive jaundice model with the common bile duct hanged on the abdominal wall. Five mice were randomly selected to testify whether the modeling is successful. The remaining 30 mice were randomly divided into aerobic exercise, model, and control groups. The aerobic exercise group underwent treadmill adaptive training for 1 week. At 1-2 days, the treadmill slop was 0° with the speed of 6 m/min, 20 min/d. At 3-4 days, the treadmill slop was 5° with the speed of 8 m/min, 40 min/d. At 5-6 days, the treadmill slop was 8° with the speed of 10 m/min, 60 min/d. After adaptive training, the treadmill slop was kept at 8° with the speed of 10 m/min, 60 min/d, and 6 d/week. The samples were removed under anesthesia at 7 days to detect each index. RESULTS AND CONCLUSION:(1) Compared with the control group, the serum concentrations of total bilirubin, total bile acid, glutamate pyruvate transaminase, glutamic oxalacetic transaminase and alkaline phosphatase were significantly increased in the model group(P < 0.01). The aerobic exercise group showed different degrees of reduction compared with the model group(P < 0.05, P < 0.01).(2) In the model group, hematoxylin-eosin staining showed the hepatocytes with large-area fibrosis and disordered hepatic cord, vacuolar, degeneration and necrotic symptoms. The fibrosis degree in the aerobic exercise group was lower than that in the model group.(3) Compared with the model group, the expression levels of LincRNA-p21 protein and mRNA in the aerobic exercise and control groups were increased(P < 0.01), and the control group was higher than in the aerobic exercise group. The expression levels of Notch-1, Jagged-1, NICD, and HES-1 protein and mRNA were highest in the model group(P < 0.01), followed by aerobic exercise group.(4) To conclude, aerobic exercise can promote the high expression of LincRNA-p21, thereby inhibiting the Notch pathway to participate in the process of liver fibrosis in mice after obstructive jaundice, and can regulate the repair after liver injury to some extent.