异常光周期所致昼夜节律紊乱对大鼠腓肠肌时钟基因和葡萄糖摄取相关基因表达节律的影响

Effects of circadian misalignment induced by abnormal photoperiod on expression rhythm of clock genes and glu‐cose uptake related genes in gastrocnemius in rats

目的探讨昼夜节律紊乱(CM)对大鼠腓肠肌时钟基因和葡萄糖摄取相关基因表达节律的影响。方法雄性Wistar大鼠36只分为昼夜节律正常(CA)组和CM组,每组18只。造模第61天行ClockLab行为学检测。造模第85天行腹腔注射糖耐量试验和生理指标检测。第91~92天于8:00、12:00、16:00、20:00、24:00、4:00处死大鼠,收集腓肠肌组织,逆转录实时定量聚合酶链反应(RT-qPCR)检测Bmal1、Clock、Per2、Tbc1d1、Glut4、Pgc1α的mRNA。结果CM组昼夜节律周期延长(t=-6.557,P<0.001)、振幅下降(t=2.326,P=0.030),腹腔注射糖耐量试验血糖曲线下面积减少(t=-2.622,P=0.016)。腓肠肌不同时间Bmal1(F=6.691,P<0.001)、Clock(F=4.188,P=0.007)、Per2(F=10.893,P<0.001)、Tbc1d1(F=3.411,P=0.018)、Glut4(F=5.439,P=0.002)、Pgc1α(F=15.376,P<0.001)表达有显著性差异,两组间腓肠肌Bmal1(F=5.020,P=0.035)、Per2(F=8.996,P=0.006)、Tbc1d1(F=51.111,P<0.001)、Pgc1α(F=10.177,P=0.004)表达有显著性差异,CM组腓肠肌24 h总Tbc1d1表达显著下降(t=4.349,P<0.001)。结论异常光周期所致CM可导致大鼠糖耐量下降,这可能与大鼠腓肠肌Tbc1d1表达下降以及Bmal1、Per2、Pgc1α的转录节律改变有关。

Objective To investigate the impacts of circadian misalignment on glucose uptake of skeletal muscle and metabolism in rats.Methods A total of 36 male Wistar rats were divided into circadian alignment(CA, normal light-dark cycles, n = 18) and circadian misalignment(CM, shifted light-dark cycles, n = 18) groups. ClockLab behavior analysis was performed for 18 days(61 to 78 days after modeling). Intraperitoneal injection glucose tolerance test and physiologic measures were performed 85 days after modeling. They were euthanized 91 to 92 days after modeling, at 8:00,12: 00, 16: 00, 20: 00, 24: 00 and 4: 00 next day. Gastrocnemius tissue was collected and measured for Bmal1,Clock, Per2, Tbc1d1, Glut4 and Pgc1α by reverse transcription real-time quantitative polymerase chain reaction(RT-qPCR).Results The circadian cycle increased(t =-6.557, P < 0.001), the amplitude decreased(t = 2.326, P = 0.030) and the area under curve(AUC) of the blood glucose of intraperitoneal glucose tolerance test decreased(t =-2.622, P =0.016) in CM group. In gastrocnemius, there was difference in the expression of the Bmal1(F = 6.691, P <0.001), Clock(F = 4.188, P = 0.007), Per2(F = 10.893, P < 0.001), Tbc1d1(F = 3.411, P = 0.018), Glut4(F =5.439, P = 0.002) and Pgc1α(F = 15.376, P < 0.001) across different time;meanwhile, there was difference in the expression of Bmal1(F = 5.020, P = 0.035), Per2(F = 8.996, P = 0.006), Tbc1d1(F = 51.111, P < 0.001)and Pgc1α(F = 10.177, P = 0.004) between groups, and the total Tbc1d1 expression decreased in CM group(t =4.349, P < 0.001).Conclusion CM induced by shifted light-dark cycles may lead to glucose tolerance impairment in rats, which may be related to the decreased expression of Tbc1d1 and the changes of transcription rhythm of Bmal1, Per2 and Pgc1α in gastrocnemius.