| Objective: To clarify the intervention effect and mechanism of salidroside on lung structure destruction and pulmonary hypertension in smoking rats.Methods: COPD rat model and pulmonary hypertension rat model were established by passive smoking alone.Thirty-six male SD rats were randomly divided into two groups: control group(n = 9)and COPD model group(n = 27).Four months later,three rats were randomly selected from each group to evaluate COPD model by lung function and pathological examination.The remaining rats were divided into 5 groups:blank group: control group rats + placebo;Smoking cessation group:COPD model group + placebo;Smoking cessation + intervention group:COPD model group rats + salidroside intervention;Continuous smoking group: COPD model group + continuous smoking + placebo;Continuous smoking + intervention group: COPD model group rats + continuous smoking + salidroside intervention.Placebo was given 0.9% sodium chloride injection by gavage at 1ml/100 g,twice a day for 2 months.Salidroside intervention was administered by gavage at a concentration of25mg/ml and a dose of 1ml/100 g each time,twice a day for 2 months.Subsequently,lung ventilation function of rats in each group was detected,right ventricular systolic pressure of rats in each group was measured by right ventricular puncture method,and right ventricular hypertrophy index was measured for the hearts of the major rats.The damage of lung structure and remodeling of pulmonary artery were observed under light microscope.Tunel marker was used to detect the proportion of lung tissue apoptosis in each group.Realtime-PCR and Western-blot were used to detect the m RNA and protein expression levels of BIP,CHOP,Bcl-2,Bim,PUMA and DR5 genes,respectively.The protein levels and activity of Caspase8 and Caspase9 were detected by Western-blot and immunofluorescence.Results:1.Comparision of the pulmonary ventilation function in each group:peak inspiratory flow(PIF),peak expiratory flow(PEF),minute volume(MV),forced vital capacity(FVC),maximum mid-expiratory flow(MMEF)were significantly decreased in COPD model group compared with control group;The smoking cessation group was lower than the blank group,the continuous smoking group was lower than the smoking cessation group,the continuous smoking + intervention group was lower than the smoking cessation + intervention group;The smoking cessation+ intervention group was higher than the smoking cessation group,and the continuous smoking + intervention group was higher than the continuous smoking group(all P < 0.05).2.Comparision of the right ventricular systolic blood pressure and the right ventricular hypertrophy index in each group: the smoking cessation group was higher than the blank group,the continuous smoking group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the smoking cessation +intervention group;the smoking cessation + intervention group was less than the smoking cessation group,the continuous smoking + intervention group was less than the continuous smoking group(all P<0.05).3.Pathological morphology of lung tissue and pulmonary vessels in each group: the structure of the control group was generally normal.COPD model group: inflammatory cell infiltration background;Partial rupture of alveolar wall;The small airway epithelial cells were exfoliated,the smooth muscle of the canal wall was thickened unevenly,and the lumen was narrowed.Inhomogeneous proliferation of smooth muscle in pulmonary artery and stenosis of lumen.Rats in the smoking cessation group: the above changes could be seen,which were less severe than those in the COPD model group and significantly more severe than those in the blank group.The above conditions in the smoking cessation +intervention group were better than those in the smoking cessation group.Continuous smoking group compared with the smoking cessation group,the above situation was significantly worse,especially the obvious proliferation and hypertrophy of the smooth muscle of the pulmonary artery wall,and the irregular narrowing of the lumen.The above changes were also observed in the continuous smoking + intervention group,which was less severe than that in the continuous smoking group,but more severe than that in the smoking cessation + intervention group.4.Comparision of Lung structural cell apoptosis ratio in each group:the smoking cessation group was higher than the blank group,the continuous smoking group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the smoking cessation + intervention group;the smoking cessation +intervention group was less than the smoking cessation group,the continuous smoking + intervention group was less than the continuous smoking group(all P < 0.05).5.Comparision of the m RNA and protein expression levels of BIP gene in each group: the smoking cessation group was less than the blank group,the continuous smoking group was less than the smoking cessation group,the continuous smoking + intervention group was less than the smoking cessation + intervention group;the smoking cessation +intervention group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the continuous smoking group(all P < 0.05).6.The m RNA and protein expression levels of CHOP gene: the smoking cessation group was higher than the blank group,the continuous smoking group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the smoking cessation + intervention group;the smoking cessation + intervention group was less than the smoking cessation group,the continuous smoking+ intervention group was less than the continuous smoking group(all P <0.05).7.Comparision of the m RNA and protein expression levels of Bcl-2、Bim、Puma gene and the protein levels and activityin of Caspase8 in each group : The m RNA and protein expression levels of Bcl-2gene : the smoking cessation group was less than the blank group,the continuous smoking group was less than the smoking cessation group,the continuous smoking + intervention group was less than the smoking cessation + intervention group;the smoking cessation + intervention group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the continuous smoking group(all P < 0.05).Comparision of the m RNA and protein expression levels of Bim 、 PUMA gene and the protein levels and activity of Caspase9 in each group: the smoking cessation group was higher than the blank group,the continuous smoking group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the smoking cessation + intervention group;the smoking cessation + intervention group was less than the smoking cessation group,the continuous smoking + intervention group was less than the continuous smoking group(all P < 0.05).8.Comparision of the m RNA and protein expression levels of DR5 gene and the protein levels and activity of Caspase8 in each group: the smoking cessation group was higher than the blank group,the continuous smoking group was higher than the smoking cessation group,the continuous smoking + intervention group was higher than the smoking cessation + intervention group;the smoking cessation + intervention group was less than the smoking cessation group,the continuous smoking+ intervention group was less than the continuous smoking group(all P <0.05).Conclusion: Salidroside may play a protective role in smokingrelated COPD and pulmonary hypertension in rats by inhibiting the endoplasmic reticulum stress CHOP-Bcl-2 and CHOP-DR5 signaling pathways,accordingly reducing apoptosis,alleviating lung structural damage and pulmonary hypertension. |
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