Effect And Mechanism Of Exogenous Hydrogen Sulfide On Lung Tissue Apoptosis In Rats With Paraquat Poisoning

ObjectiveTo establish acute respiratory distress syndrome rat model with paraquatpoisoning,observe the change of lung tissue apoptosis and expression of apoptosisprotein.Study the influence of different doses of hydrogen sulfide intervened on lungtissue apoptosis and its mechanism.MethodAccording to random number table,60SD rats were randomly divided intonormal saline control group, the NaHS group, the PQ group, PQ+NaHS low-dosegroup, PQ+NaHS middle dose group, the PQ+NaHS high dose group,a total of6groups,10in each group.PQ group and L, M, H group were of disposable gavagePQ80mg/kg to create PQ infected model, while C and N group was of disposablegavage such as volume normal saline.L, M, H groups were intrapulmonary injectedNaHS14umol/kg,28umol/kg,56umol/kg respectively3hours from PQ injection,Cgroup and PQ group with intraperitoneal injection of the same volume of normalsaline,group NaHS with high doses NaHS as56umol/kg.When infected24h to be putto death with all the rats.Drawing abdominal aortic artery blood for gasanalysis;Measure lung coefficient（LW/BW）and Lung wet/dry weight ratio （W/D）according to the double lung taken.Then observe the lung tissue morphology changeunder light microscope,calculate the alveolar damage ratio （IQA）;Usingimmunohistochemical staining SP method to detect lung tissue Bcl-2, Bax, Caspase-3and Caspase-9protein expression, calculation of the Bcl-2/Bax ratio;To detect lungtissue apoptosis rate with terminal deoxyribonucleotide transferase (TdT) mediateddUTP Nick end labeling method (TUNEL method).Experimental data were presentedas mean±standard deviation (x±s),multiple groups were compared with ANOVA test(one-way classification ANOVA),pairwise comparisons using LSD-t test.Personcorrelation coefficient were used to analyze the correlation between the normal doublevariables.P <0.05was considered statistically significant.Result1．General situation and survival condition in ratsThe experimental rats with no deaths.There was normal spirit, feeding,sleep,drinking and behavior for C and N group rats. After gavage,low spirits,drowsiness,reducing the volume of feeding and drinking water shown on the PQgroup,company with head nystagmus, walking instability. Shortness ofbreath,cyanotic lips and feet can be observed in PQ group. Part of them hadhyperemia eye and epistaxis. After intraperitoneal injection of NaHS,the abovepoisoning symptoms were improved in varying degrees for group of L、M and Hwhile H group improved the most obvious.2．Change of lung tissue morphologyThe lung of C and N group is normal with integrity lung tissue structure;Adversely,PQ group’s lung volume increased obviously.Microscopically,PQ group’salveolar space and pulmonary interstitial shown the changes of hemorrhage,edema.Alveolar walls were widely destructive company with thickening of alveolarinterval in different level. Part of the alveolar collapse and atelectasis, some alveolarhad compensatory emphysema.The morphology change visible under lightmicroscope in L, M, H group shown different levels improvement,while H grouprelieved most significant.Compared with group C，IQA of N group had no statisticaldifferences with C group’（sP>0.05）while PQ group’s and L、M、H group’s was higher(P<0.01). Compared with group PQ,IQA in L、M、H group was lower in different level(P<0.01), but higher than C group’s (P<0.01).3．changes of LW/BW、W/DThe differences of LW/BW、W/D between C and N group were not statisticalsignificance（P>0.05）;LW/BW、W/D of PQ group were higher than C group’s(P <0.01）; LW/BW,W/D in group of L、M、H were obviously lower than PQ group’s(P<0.05or P<0.01),but higher than C group’s (P<0.01).4．Arterial blood gas analysisThere was no statistical differences for the PaO2and PaO2/FiO2in group C and N（P>0.05）. PaO2and PaO2/FiO2of PQ group were lower than C group’s(P <0.01）;Compare with PQ group, PaO2and PaO2/FiO2in the group of M,H was rise(P<0.05orP<0.01). PaO2and PaO2/FiO2in the group of L,M,H was lower than C group’s(P<0.01).5．The change of lung tissue apoptosis proteinA small amount of Bcl-2,Bax, Caspase-3and Caspase-9protein expression onthe lung tissue of group of C and N;Mainly locate in alveoli, bronchial epithelial cellsand endothelial cells;Compared with group of C,Bcl-2protein express to enhance（P<0.01），Bax protein obviously express to enhance（P<0.01）in the lung tissue ofPQ group,The ratio of Bcl-2/Bax was decreased obviously（P<0.01）,Caspase-3andCaspase-9protein obviously express to enhance（P<0.01）. Compared with group ofPQ, Bcl-2protein in group of L and M a little express to enhance(P>0.05), Bcl-2protein obviously express to enhance in group of H（P<0.01）, Bax protein obviouslyexpress to weaken in group of M and H（P<0.01）, Bcl-2/Bax was higher obviously ingroup of L、M and H（P<0.01）, Caspase-3and Caspase-9protein obviously expressto weaken in group of M and H（P<0.01）。6．Changes in the lung tissue cell apoptosisC and N group had a little amount of apoptosis cells;Compared with group ofC,PQ group had a more high AI（P<0.01）；L、M、H group had a lower AI than PQgroup（P<0.05or P<0.01）while still higher than control group’s（P<0.01）.Conclusion1、Lung tissue cell apoptosis increases when acute respiratory distress syndromeinduced in rats which lung were injury with PQ poisoning.2、PQ poisoning rat lung tissue Bcl-2, Bax protein expression increased, Bcl-2/Bax ratio decreased, Caspase-3and Caspase-9expression increased too.3、Given different doses of exogenous H2S donor NaHS to PQ poisoning rats canvarying degrees reduce their lung injury，up-regulate of Bcl-2protein expression,down regulate Bax, Caspase-3, Caspase-9protein expression.NaHS has a certainprotective effect on ARDS induced by paraquat.