Objective : To pathological changes and inducible nitric oxide synthase(iNOS), phosphorylated insulin receptor substrate 1 serine 307(p-IRS1ser 307), phosphorylated protein kinase B serine 473(p-AKTser 473), glycogen synthase kinase-3β(GSK-3β), and gluconeogenic synthase(GS) proteins were observed in the liver of rats under the condition of chronic intermittent hypoxia-replicated oxygen in control. And to explore the role of iNOS/IRS1/AKT/GSK-3β signaling pathway in chronic intermittent hypoxia-induced insulin resistance. Methods : Forty SD rats were randomly divided into a control group(NC group) and an experimental group(CIH group), with 20 rats in each group. The NC group was placed in a normoxic environment for 12 weeks, while the CIH group was first subjected to intermittent hypoxia for 8 weeks, and then resumed normoxic rearing until the 12th week. Fasting blood glucose(FBG) and fasting insulin(FINS) were measured at baseline, week 8 and week 12, and liver tissues were taken for pathology and measurement of iNOS, p-IRS1ser 307, p-AKTser 473, GSK3β and GS levels, to compare the differences between groups. Results: t baseline, there was no significant difference in liver pathology between the two groups, and the observed indexes were not statistically significant(P>0.05); at 8 weeks, compared with the NC group, liver pathology in the CIH group showed significant disorganization of hepatic blood sinusoids and hepatocyte cords, obvious hepatocyte edema, smaller nuclei, increased lymphocyte infiltration, and a small number of fat vacuoles, significantly higher levels of FBG, FINS, insulin resistance index(HOMA-IR), iNOS mRNA, p-IRS1ser 307 protein, GSK-3β protein levels, and decreased p-AKTser 473 protein and GS protein levels, all of which were statistically significant(allP<0.05). IRS1ser 307 protein, GSK-3β protein levels were increased, p-AKTser 473 protein and GS protein levels were decreased, and the differences were statistically significant(allP<0.05); at 12 weeks, no lymphocyte infiltration was seen in the CIH group compared with that of the NC group and fat vacuoles significantly increased, and there was no improvement in the other pathological damage that had already occurred, and the levels of p-AKTser 473 protein significantly increased. AKTser 473 protein level significantly increased, p-IRS1ser 307 protein and GS protein levels were significantly reduced, all of which were statistically significant(allP<0.05), and the rest of the observational indexes were not statistically significant. Pearson′s correlation analysis showed that HOMA-IR of CIH group was significantly positively correlated with the levels of iNOS mRNA, p-IRS1ser 307 protein, and GSK-3β protein at 8 weeks(r=0.874, 0.817,0.872;allP<0.05), and significantly negatively correlated with the levels of p-AKTser 473 protein and GS protein(r=-0.886,-0.879;allP<0.05). Conclusion Chronic intermittent hypoxia can lead to hepatic pathological damage that cannot be reversed even by reoxygenation interventions and may mediate the development of insulin resistance by upregulating the IRS1/AKT/GSK-3β signaling pathway through the upregulation of iNOS mRNA expression.

Objective : By observing the changes of interleukin-22 ( IL-22) ，signal transduction and transcriptional activator 3 (STAT3) ，fasting blood glucose ( FBG) and fasting insulin ( FINS) of rats under the circumstance of chronic intermittent hypoxia and reoxygenation，to explore the role of IL-22 / STAT3 pathway in insulin resistance in- duced by chronic intermittent hypoxia． Methods : 4 SD rats were randomly divided into control group (NC group) and intermittent hypoxia group ( CIH group) ，with 12 rats in each group．NC group was placed in normoxia environment for 12 weeks，while CIH group was first given intermittent hypoxia for 8 weeks and then resumed normoxia feeding until 12 weeks．FBG，FINS，IL-22 and p-STAT3 / STAT3 levels were measured at baseline，week 8 and week 12 in both groups，and insulin resistance index (HOMA-IR) was calculated．The differences between the two groups were compared. Results : ① There was no significant difference of the observation indexes between the two groups at baseline (P＞0. 05) ．At 8 weeks，the levels of FBG，FINS and HOMA-IR in CIH group were higher than those in NC group (P＜0. 05) ，and the levels of IL-22 were lower than those in NC group (P ＜0. 05) ．p-STAT3 / STAT3 showed a decreasing trend，but not statistically significant．At 4 weeks of reoxygenation，there were no significant differences in FBG，FINS，HOMA-IR and IL-22 levels between the two groups (P ＞0. 05 ) ．p-STAT3 / STAT3 in CIH group was significantly higher than that in NC group ( P ＜0. 05 ) . ② Spearman rank correlation analysis showed that HOMA-IR was negatively correlated with IL-22 and p-STAT3 / STAT3 ( all P ＜0. 05) ． Conclusion Chronic intermittent hypoxia can inhibit the expression of IL-22 / STAT3 signaling pathway，IL-22 / STAT3 signaling pathway may mediate insulin resistance induced by chronic intermittent hypoxia.

Objective : To investigate the role of endoplasmic reticulum stress in hepatic insulin resistance induced by intermittent hypoxia in rats． Methods : Twenty-four SD rats were randomly divided into control group ( NC group) and intermittent hypoxia group ( CIH group) ．The NC group was placed in a normoxia environment for 12 weeks，and the CIH group was given intermittent hypoxia for 8 weeks，and then returned to normoxia until the 12th week．In both groups，fasting blood glucose (FBG) ，fasting insulin (FINS) ，and liver inositol-requiring enzyme- 1 α(IRE1 α) ，X-box binding protein 1s(XBP1s) ，forkhead box transcription factor O1 (FoxO1) ，activating transcription factor-6(ATF6) ，cAMP-response element binding protein( CREB) ，CREB-regulated transcription coacti- vator-2( CRTC2) ，double-stranded RNA-dependent protein kinase-like ER kinase ( PERK) ，eukaryotic initiation factor 2 α(eIF2 α) ，protein kinase B ( AKT) ，phosphoenolpyruvate carboxykinase ( PEPCK) ，glucose-6-phosphat- ase( G6Pase) mRNA were measured at baseline，week 8，and week 12 . Results : There was no significant differ- ence in each observation index between the two groups at baseline ; at 8 weeks，the levels of FBG，FINS and the mRNA levels of IRE1α , XBP1s，ATF6，PERK，eIF2 α , PEPCK and G6Pase in the CIH group were higher than those in the NC group (P＜0. 05) ，while the mRNA levels of CREB，CRTC2 and AKT were lower than those in the NC group (P＜0. 05) ; at 12 weeks，there was no significant difference in each observation index between the two groups．Pearson correlation analysis showed(8th week of intermittent hypoxia group) : homeostasis model as- sessment-insulin resistance(HOMA-IR) was positively correlated with FoxO1，CREB，CRTC2 and PERK，eIF2 α mRNA levels (r = 0. 172，0. 595，0. 183，0. 702，0. 608 ; P＜0. 05) while it was negatively correlated with IRE1α , XBP1s，ATF6，AKT mRNA levels (r = －0. 422 ，－0. 327 ，－0. 309 ，－0. 399 ; P＜0. 05) ． Conclusion Intermittent hypoxia can lead to insulin resistance，and endoplasmic reticulum stress may mediate this effect.