Preliminary Study Of Theeffect Of IH On Pulmonary Fibrosis And Its Mechanism In A Mouse Model Of OSA

Obstructive sleep apnea is a chronic sleep apnea disease characterized by recurrent upper airway partial or complete obstruction during sleep,which has a prevalence of 2% 4%,untreated OSAS patients 5 years mortality rate of 11% to 13%,a serious threat to the patient's health and life.Intermittent hypoxia(IH)is a unique pathophysiological change of OSAS,which is characterized by hypoxia-reoxygenation,similar to ischemia / reperfusion injury,and is considered to be associated with OSAS multiple complications such as cardiovascular and cerebrovascular Disease,metabolic disorders,cognitive dysfunction,genitourinary dysfunction and cancer and so on,the harm to the body can not be underestimated.In recent years,OSAS and pulmonary interstitial fibrosis has gradually been found by the researchers,pulmonary interstitial fibrosis is a progressive development,lethal,unknown etiology of interstitial lung disease,it is by the fibroblasts / Fibroblasts(fibroblasts / myofibroblasts)accumulation and collagen(collagen)and other extracellular matrix(extracellular matrix,ECM)caused by excessive deposition.The average survival time of the patients with pulmonary fibrosis was 2 years,and the survival rate of the patients was 30% ~ 50%,the mortality was high and the prognosis was poor.At present,there was a lack of effective treatment in the clinical treatment of pulmonary fibrosis.OSAS is a systemic disease that can combine multiple diseases,and oxidative stress is a common mechanism of OSAS and pulmonary interstitial fibrosis.This study will explore the effect of OSAS model IH on pulmonary fibrosis and discuss the effect of oxidative stress on it,and provide experimental basis and theoretical basis for further clinical research.Objectives 1.To investigate the effect of OSA model IH on bleomycin-induced pulmonary fibrosis in mice.2.To investigate the effect of OSAS model IH on activation and extracellular matrix secretion of mouse lung fibroblasts.MethodThe model of pulmonary fibrosis induced by bleomycin was established.The rats were randomly divided into three groups: N group(normoxia group),IH group(intermittent hypoxia group)and IH + T group(Tempol intervention group).For the IH + T group,Tempol was injected intraperitoneally half an hour before IH treatment.Three groups of mice were placed in self-made IH exposure containers,and the compressed air was continuously delivered to group N in the period of 10: 00-16: 00 The mixed cells of oxygen and nitrogen were intermittently delivered to IH group and IH + T group.?-SMA was detected by Western blot.Cultured fibroblasts in cell culture box could pass the cell line MLg cells to 80-90 % Of the adjusted lung fibroblasts were randomly divided into 5 groups.Four groups were placed in the IH experimental compartment.One group was randomly selected for 1 hour before the IH treatment.The rats in the control group were cultured in the incubator for 24 h,then the cells were collected from the intermittent hypoxia group and the control group respectively.The cells of the control group were cultured in the incubator for 24 hours,and then the cells were treated with OSAS model IH stimuli,1h,4h,8h and T + 8h respectively.The expression of ?-SMA and Col1a1 was detected by q RT-PCR.The expression of ?-SMA and type I collagen(COL1)protein was detected by Western blot.The SPSS16.0 software package was used to analyze the data,and the data were expressed as x ± s.The one-way ANOVA was used in the study group,P <0.05,the difference was significant(P <0.01).Results 1.Effect of OSAS model IH on the expression of ?-SMA protein in lung tissueinduced by bleomycin-induced pulmonary fibrosis model and the effect of Tempol intervention on the expression of ?-SMA proteinWestern blot analysis showed that the expression level of ?-SMA protein IH group in bleomycin-induced pulmonary fibrosis model was significantly higher than that in normoxic control group(P <0.05)The expression of ?-SMA protein in IH + T group was lower than that in IH group,but it was higher than that in normoxic control group(P <0.05).2.Effects of different intermittent hypoxia on the expression of ?-SMA in lung MLg fibroblasts and the effect of Tempol intervention on the expression of ?-SMA proteinThe relative expression of ?-SMA m RNA in lung MLg fibroblasts of IH1 h,IH4h and IH8h mice was significantly higher than that in normoxic control group(P <0.05).IH1 h,IH4h,IH8h mice lung MLg cells The expression level of ?-SMA m RNA was increased with the prolongation of IH time(F = 104.3 P <0.05),and peaked at IH8h(P <0.01).Western blot analysis showed that the expression of ?-SMA protein in lung MLg fibroblasts of IH1 h,IH4h and IH8h mice was higher than that in normoxic control group(P <0.05),IH1 h,IH4h,IH8h mice lung MLg fibroblasts The expression level of ?-SMA protein was increased with the prolongation of IH time(P <0.05),and peaked at IH8h(P <0.05).The expression level of IH8h + T ?-SMA protein was lower than that of IH1 h,IH4h and IH8h(P <0.01).3.Effects of different intermittent hypoxia on the expression of COL1 in lung MLg fibroblasts and the effect of Tempol intervention on COL1 protein expressionThe relative expression of COL1 m RNA in IH1 h,IH4h and IH8h mice was significantly higher than that in normoxic control group(P <0.05).The relative expression of COL1 m RNA in IH1 h,IH4h and IH8h cells(F = 220.3 P <0.05),and reached the peak in IH8h group(P <0.01).Western blot analysis showed that the expression level of COL1 protein in lung MLg fibroblasts of IH1 h,IH4h and IH8h mice was higher than that of normoxic control group(P <0.05),IH1h,IH4h,IH8h mice lung MLg fibroblasts COL1 protein The expression level was increased with the prolongation of IH time(P <0.05),and peaked at IH8h(P <0.05).The expression level of IH8h + T COL1 protein was lower than that of IH1 h,IH4h and IH8h,but slightly higher than that of N group(P <0.01).