褪黑素对水浸束缚导致的大鼠应激性肝损伤的保护作用机制研究

Protective effects and mechanism of melatonin on stress liver injury induced by chronic water-immersion in rats

目的探究褪黑素对水浸束缚导致的大鼠应激性肝损伤的作用及分子机制。方法按照体重将SD大鼠随机分成4组:正常组、模型组和低、高2个剂量实验组,每组8只。大鼠每日水浸束缚10 h制备应激性肝损伤模型。每日束缚前1 h,低、高2个剂量实验组分别腹腔注射2.5和5.0 mg·kg^(-1)褪黑素,正常组和模型组均腹腔注射等体积生理盐水,连续干预21 d。以试剂盒法检测谷丙转氨酶(GPT)含量;以酶联免疫吸附法检测白细胞介素-1β(IL-1β)水平;以蛋白质印迹法检测肝组织内AMP依赖的蛋白激酶(AMPK)、过氧化物酶体增殖剂激活受体α(PPARα)和肉毒碱棕榈酰基转移酶-1α(CPT1a)蛋白表达。结果正常组、模型组和低、高2个剂量实验组的GPT分别为(3.94±0.73),(10.91±2.17),(5.81±1.82)和(6.27±1.70)U·L^(-1);IL-1β分别为(67.16±5.05),(143.29±7.05),(118.34±9.51)和(102.16±6.77)pg·mL^(-1)。以上指标,模型组与正常组比较,或2个剂量实验组与模型组相比,差异均有统计学意义(P<0.05,P<0.01,P<0.001)。这4组的AMPK蛋白相对表达量分别为1.00±0.00,0.59±0.16,0.71±0.21和0.94±0.18;这4组的PPARα蛋白相对表达量分别为1.00±0.00,0.56±0.15,0.75±0.11和0.85±0.07;这4组的CPT1a蛋白相对表达量分别为1.00±0.00,0.46±0.12,0.72±0.19和0.90±0.16。上述指标:模型组与正常组比较,或高剂量实验组与模型组相比,差异均有统计学意义(P<0.05,P<0.01,P<0.001)。结论褪黑素对应激性肝损伤具有一定的保护作用,其机制可能与下调炎症因子的表达、抑制肝中脂质的积累,并上调AMPK、PPARα和CPT1a蛋白表达有关。

Objective To investigate the protective effects and molecular mechanisms of stress-induced liver injury induced by water immersion restraint rats. Methods Rats were randomly divided into four groups: normal group, model group and low, high dose experimental groups, 8 rats in each group. The stress-induced liver injury model was established by water immersion and restraint for 10 h. Experimental-L and experimental-H were intraperitoneally injected with 2.5 and 5.0 mg·kg-1 melatonin 1 h before modeling for consecutive 21 d while the other two groups were 0.9 % NaCl.Glutamic-pyruvic transaminase(GPT) was detected by kit. Interleukin-1β(IL-1β) was detected by enzyme linked immunosorbent assay.The protein expressions of AMP-activated protein kinase( AMPK), peroxisome proliferators-activated receptor alpha( PPARα) and carnitine palmitoyltransferase 1 a( CPT1 a) were detected by Western blot. Results The GPT levels of normal group,model group and experimental-L and experimental-H groups were( 3. 94 ± 0. 73),( 10. 91 ± 2. 17),( 5. 81 ± 1. 82) and( 6. 27 ± 1. 70) U·L-1,respectively;IL-1β levels in the 4 groups were( 67. 16 ± 5. 05),( 143. 29 ± 7. 05),( 118. 34 ± 9. 51) and( 102. 16 ± 6. 77) pg·mL-1. Comparison between model group and normal group,or between experimental groups and model group,the difference of above factors were significant( P < 0. 05,P < 0. 01,P < 0. 001).The protein expression of AMPK in the four groups were 1. 00 ± 0. 00,0. 59 ± 0. 16,0. 71 ± 0. 21 and 0. 94 ± 0. 18,respectively;the protein expression of PPARα in the four groups were 1. 00 ± 0. 00,0. 56 ± 0. 15,0. 75 ± 0. 11 and0. 85 ± 0. 07,respectively;the protein expression of CPT1 a in the four groups were 1. 00 ± 0. 00,0. 46 ± 0. 12,0. 72 ± 0. 19 and 0. 90 ± 0. 16, respectively. Comparison between model group and normal group,or between experimental-H group and model group,the difference of above factors were significant( P < 0. 05,P < 0. 01,P < 0. 001). Conclusion Melatonin has a protective effect on stress-induced liver injury,and its mechanism may be related to downstream inflammatory factors,inhibition of lipid accumulation in the liver,and up-regulation of AMPK,PPARα and CPT1 a.