| Objective Through building the intermittent hypoxic rats model, to measure the content of fasting blood glucose(FBG) and fasting insulin(FINS) to calculate homeostatic model assessment of insulin resistance index(HOMA-IR), and to test expression of translocation of glucose transporter(GLUT) 4 and protein kinase B(PKB/Akt2) in skeletal muscle cells of rats, to discuss the effects of the intermittent hypoxia on the insulin resistance, and possible mechanism of GLUT4 and Akt2 on insulin resistance induced by intermittent hypoxia.Methods Forty healthy adult male Sprauge-Dawley rats were divided into 5 groups by random number table method: normal control group(NC group), intermittent hypoxia for 2 weeks group(IH2 group), intermittent hypoxia for 4 weeks group(IH4 group),intermittent hypoxia for 6 weeks group(IH6 group)intermittent hypoxia for 8 weeks group(IH8 group). Each group had 8 hats.Rats in IH2 group, IH4 group, IH6 group and IH8 group were exposed to intermittent hypoxia 8 hour each day(9:00-17:00).Intermittent hypoxia scheme: Firsr aerating nitrogen 60 s to reduce oxygen concentration in hypoxia cabin gradually from 21% to 8%. Maintain the minimum oxygen density 10 minites and then aerating oxygen 40 s to restore oxygen concentration in hypoxia cabin gradually to 21%. The whole cycle lasted 110 s. Rats in intermittent hypoxia groups were ended being exposured to hypoxia after 2,4,6,8 weeks respectively. Rats in NC group were raised in room air for two weeks. Rats in NC group and intermittent groups were anaesthetized to get specimens after two weeks and corresponding intermittent hypoxic exposure respectively. Fasting blood glucose and fasting blood insulin were measured by blood glucose meter and double-antibody sandwich ELISA separately, and then calculated HOMA-IR. GLUT4 and Akt2 protein in skeletal muscle cells of rats were analyzed by immunohistochemistry, and the corresponding average grey value were determined by Scanscope digital pathology scanning system. The expression of the protein was inversely showed as average gray value. And then analyzed the correlation between GLUT4 and Akt2. The datas were statistically analyzed.Results(1)Compared with NC group, FBG and HOMA-IR were higher in IH2, IH4, IH6,IH8 groups and more distinct in accordance with exposure time of intermittent hypoxia(F=87.67,211.85, all P<0.05), FINS elevated and more distinct in accordance with exposure time of intermittent hypoxia in IH2, IH4, IH6 group. However, FINS in IH8 group was lower when compared with IH6 group(F =86.04, P<0.01).(2)Compared with NC group, average gray value of GLUT4 and Akt2 were higher in IH2, IH4, IH6, IH8 groups, and more significant with intermittent hypoxia exposure time(F=288.63, 155.61, P all < 0.05).(3)Pearson correlation analysis showed that the average grey value of GLUT4 and Akt2 was positively correlated with HOMA-IR respectively(r=0.937, 0.917, P<0.01), the average grey value of GLUT4 was positively correlated with of Akt2(r=0.895,P<0.05).Conclusion(1) Intermittent hypoxia can induce insulin resistance, degree of which increased more notable with intermittent hypoxia exposure time.(2) Intermittent hypoxia can induce the expression of GLUT4 and Akt2 in skeletal muscle cells of rats reducing,and more notable with intermittent hypoxia exposure time.(3)In the intermittent hypoxia rats, insulin resistance were related to both with GLUT4 and Akt2 protein expression levels decline, and the change of two kinds of protein expression levels had significant correlation which indicated that GLUT4 and Akt2 protein play a synergistic effect in insulin resistance induced byintermittent hypoxia. |
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