| Objective:Rats were exposed to cigarette smoke?CS?to establish the lung injury model,whose purpose is to observe the effect of CS on pulmonary function and the damage of lung tissue induced by mitochondrial dynamic balance disorder.Moreover,some preliminary mechanism researches were arranged to provide new ideas for the treatment of Chronic Obstructive Pulmonary Disease.Methods:1.Eighty SD male rats were randomly divided into four groups:Control group,cigarette smoke group?CS group?,sulforaphane group?SFN group?,cigarette smoke combined with sulforaphane treatment group?CS+SFN group?.Rats in CS and CS+SFN group were exposure to cigarette smoke for one month and three months,respectively:twenty cigarettes per time,2times/day,the interval between two times is 5h,5 days per week.Rats in SFN and CS+SFN group were intraperitoneally injected with SFN(0.5 mg·kg-1)1h before daily smoking,and the Control group was given the same dose of solvent?containing 1%DMSO in PBS?.The pulmonary function of the rats were tested in both the awake and anesthesia.2.HE staining was used to observe the morphological changes of lung tissue after CS and SFN treatment.3.Morphological changes of type II epithelial cells and mitochondrion of rat lung tissuewere detected by transmission electron microscopy after exposed to CS and SFN for three months.4.Western blot was used to detect the protein expression of LC3B,Drp1,Mfn2,PINK1,Parkin in both total protein level and mitochondrion level.Results:1.Compared with Control group,the weight gain of rats in the CS group was slow,which was statistically significant from the third week?p<0.05?.2.CS causes a decrease in expiratory volume and inspiratory volume per minute,an increased lung resistance?p<0.05?,and a decreased dynamic compliance.After SFN pretreatment,the above symptoms can be improved.3.HE staining results showed that the morphology of lung tissue after CS treatment was mainly characterized by thickening of alveolar wall,infiltration of inflammatory cells in the interstitium,edema fluid in alveolar cavity,SFN can alleviate the above damage.4.The results of transmission electron microscope showed that compared with the Control group,the vacuoles in the alveolar type II epithelial cells of the CS group were significantly increased,a large number of lamellar bodies were broken,and the mitochondria were swollen and deformed,showing perinuclear aggregation.The lysosomes in the CS+SFN group increased,and a small amount of phagocytic vacuoles were observed.5.CS may induce autophagy in lung tissue.Total protein was detected by Western blot:compared with Control group,the ratio of LC3-II/LC3-I in CS group was increased,but it was not statistically significant?p>0.05?.6.CS can induce mitophagy in lung tissue.?1?The total protein was detected by Western blot:compared with Control group,the expression of Mfn2 decreased in CS group in one month?p>0.05?,however,the expression levels of Drp1?p>0.05?,PINK1?p>0.05?,Parkin?p<0.05?increased.Three months later,the expression levels of Mfn2,Drp1 and Parkin in CS group increased,but the expression of PINK1 decreased,but they were not statistically significant?p>0.05?.?2?Western blot was used to detect mitochondrial protein:compared with Control group,after CS stimulation for one month,the expression of Drp1?p<0.05?and PINK1?p<0.01?increased significantly,and the expression of Mfn2 and Parkin decreased?p>0.05?.After three months,the expression of PINK1 in the CS group decreased?p>0.05?,the expression of Mfn2 decreased,almostly disappeared?p>0.05?,but the expression of Parkin?p<0.05?and Drp1?p>0.05?increased.Conclusions:1.Pulmonary ventilation function of rats impaired causing by CS,airway resistance increased.2.CS can damage lung tissue,causing alveolar type II epithelial cells and mitochondrial morphological change.3.PINK1-Parkin signaling pathway is involved in the regulation of increased mitophagy in lung injury induced by CS. |
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