| Objective Obstructive sleep apnea-hypopnea syndrome(OSAHS)combined with obese patients was studied in a rat model of chronic intermittent hypoxia(CIH)combined with a high-fat diet to investigate the effects of CIH and high-fat diet on rat heart tissue injury and extracellular-5'-nucleotidase(CD73)expression.The effect of reoxygenation in the treatment of clinical continuous positive airway pressure(CPAP)therapy with a reoxygenation model provide new ideas for the clinical treatment of OSAHS.Methods A rat model of chronic intermittent hypoxia combined with a high-fat diet was established.48 SPF grade male Wistar rats were randomly divided into 4 groups according to the random number table method,12 in each group.Group A: Control group(normoxic and common diet);Group B: High-fat group(normoxic and high fat diet);Group C: Intermittent hypoxia(intermittent hypoxia and common diet);Group D: Intermittent hypoxia combined with high fat diet(intermittent hypoxia and high fat diet).Group A and group C were given normal feed;group B and group D were given high-fat diet feed.Groups C and D were placed in an intermittent hypoxic environment of 8 h/d,while groups A and B were given intermittently compressed air.Six weeks after the experiment,6 rats were randomly selected from each group.Serum levels of triglyceride(TG)and low-density lipoprotein cholesterol(LDL-C)were measured.Heart tissue of rats was treated with hematoxylin-eosin.After HE staining,the pathological changes of the heart were observed under a microscope.Immunohistochemistry and Western blot were used to detect the expression level of protein CD73 in rat cardiomyocytes.The original dietary conditions of the rats were unchanged and reoxygenated for 2 weeks.The above tests were repeated and analyzed.Results The results after CIH for 6 weeks: 1.Compared with group A,the levels of serum TG and LDL-C in group B,C,and D increased,and group D significantly increased,and the differences were statistically significant(all P<0.05).2.The results of HE showed that there was no obvious abnormality in the cardiomyocytes of group A.Part of the myocardium fibers were disordered and focal degeneration and necrosis were seen in group B and C.The damage of myocardium was most obvious in group D.The damage of myocardial cells in group D was the most obvious.The disorder of muscle fibers was observed,the cross-grain pattern was unclear,and some muscle fibers dissolved.3.Immunohistochemistry showed that compared with group A,the expression of CD73 protein in group B,C,and D was obviously increased(P<0.05),and the expression of CD73 protein in group D was significantly increased(P<0.01).4.Western blotting also showed consistent results: Compared with group A,the expression levels of CD73 protein in group B and C were obviously increased(all P<0.05),and the expression level of CD73 protein in group D was significantly increased(P< 0.01).After reoxygenation for 2 weeks,the results were as follows: 1.Compared with pre-reoxygenation,serum TG and LDL-C levels in group C and group D increased,and the differences were statistically significant(all P<0.05).2.The HE results showed: In group A: no obvious abnormalities was seen in heart tissue.In group B,some muscle fibers were seen to be disordered,with unclear cross-sectional pattern and focal degeneration and necrosis.In group C,some muscle fibers were still seen to be disordered with unclear cross-sectional pattern,but focal necrosis was decreased before reoxygenation.In group D,myocardium still showed disordered myocardial fibers,unclear cross-sectional pattern,and local muscle fiber degeneration and necrosis.The extent of necrotic lesions decreased before reoxygenation.3.Immunohistochemistry showed that compared with before reoxygenation,the protein expression of CD73 in myocardium of group C and group D were significantly decreased(P<0.01),and the difference was statistically significant.4.Western blot also showed consistent results: compared with before reoxygenation,the protein expression of CD73 in group C and group D decreased(P<0.05),and the differences were statistically significant.Conclusion 1.Chronic intermittent hypoxia and high-fat diet can cause lipid metabolism disorder and myocardial pathological damage in rats.Under chronic intermittent hypoxia combined with high-fat diet,this metabolic disorder and myocardial pathological damage were more serious.2.Both of chronic intermittent hypoxia and high-fat diet can induce the increase of CD73 expression in rat cardiac muscle tissue.Under chronic intermittent hypoxia combined with high-fat diet,the expression of CD73 in myocardium was increased significantly.3.Reoxygenation for 2 weeks did not improve the disorder of lipid metabolism in rats,but it could improve the pathological damage of myocardial tissue and significantly reduce the expression of CD73 in myocardial tissue of rats. |
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