Role Of DRP1and OPA1in Hyperoxia-induced Lung Injury Of Premature Rat

Objective:To research the role of DRP1and OPA1in Hyperoxia-Induced Lung Injury of Premature Rats which led to cell apoptosis.Methods:1.Take the pulmonary tissue cell of premature rats as the study object.Forty-eight premature Wistar rats were stochastic divided into two half.Onewas control group in which rats were exposed to210ml.L-1oxyen,the otherwas hyperoxia group in which Rats were exposed to950ml.L-1oxyen(set up amodel of hyperoxia injury of lungs).Being fed with the same routine food,thelung tissues of two groups were gained on the first day,the third day and theseventh day by which that all mice were killed with cutting neck.After that, thelung tissues were picked to do paraffin slice.2.Monitoring endex:Section of lun-gs were stained with hematoxylin eosin to observe the pathological change;Streptavidin-peroxidase immunohistochemistry was applied to observe the exp-ression and location of DRP1and OPA1as well as the ratio change in the lungcells which were protein linked with the change of plastosome;it was used todetect the apoptosis of lung cell of each premature rats by means of terminaldeoxynucleotidyl transferasemediated dUTP-biotin nick end labeling assay.3.All pstsmryters were expressed as the mean value(x)±standard difference (s),statistical analysis were carried out by using one-way analysis of variance inter-group, paired T test was carried through and LSD test was used between twogroups．Difference was considered evidence when the p.value was less than 0.05．The statistics work were pulled off by SPSS16.0software.Relation ofindex was processed by linear correlation analysis. Results:1.By using ofinverted microscopy,the classical pathologic characters of lung injury werefound out in hyperoxia group. In control group,cell were sticked to each othertightly multyang appian,cobblestone appearance change,transmittance of lightraised and particles of periplasm were sparse. Compared with control group,themount of cells in hyperoxic group decreased remarkablely，form of the cellschanged irregularly,the alveolar structure destructed obviously, Transmittanceof linght weakende, there were a lot of vacuolus,lipid droplets and cluster ofparticles in the kytoplasm.There was much cell debris filled in the blanks ofaccrescent intercellular space.Cell spacer thichende and alveolar space reduced2.DRP1protein expression was detected by the immunochistochemistry detect-ion methods: Expression of DRP1is largely in the cytoplasm of lung tissue bycomparison of the control group in which the expression of DRP1changedlittle.It could be seen the notable difference (P<0.05).The level of DRP1was(789.86±58.95)on the1d,(772.31±42.82)on the3d,and(770.39±67.8)on the7d. The expression level of DRp1(Mean±SD)began to decrease on he first day(1634.57±108.85)and apparently decreased on the second day (8008.14±530.26)，which was least on the seventh day (13132.32±594.57).3. OPA1protein expression was detected by the immunochistochemdetection methods:Expression of OPA1lessened in the cytoplasm of lung tissue by compareisonof the control group,it also could be seen the notable difference (P<0.05) On the other hand，the level of OPA1(Mean±SD)in hyperoxia group began todecrease on the first day(3126.91±264.91),and evidently decreased on the sec-ond day(1399.81±268.62),while reached the lowest on the seventh day(579.76±99.20). In control group, the level of OPA1(Mean±SD)was (3935.42±263.99)on the1d,(3764.15±281.53)on the3d,and(3907.80±231.34)7d.4DRP1andOPA1were expressed in the cytoplasm of lung tissue.Compared with the con-trol group, the ratio change of DRP1and OPA1increased with time dependen-ce in hyperoxia group which (Mean±SD)was(0.52±0.01)on the1d,(5.72±0.05)on the3d,and(22.68±0.07)on the7d;the level of DRP1/OPA1(Mean±SD)in control group was (0.200±0.01)on the1d,(0.205±0.01)on the3d,and(0.197±0.01)on the7d.5There were a small number of yellowish-brown oryellow TUNEL cell in the cytoplasm of lung tissue,on the other hand,a lot ofTUNEL-positive cells began to found TUNEL-positive cells in bronchiialepit-helial cells and alveolar epithelial cells.More time exposed to hyperoxia,moreexpression TUNEL-positive cells increased.It could be seen cell apoptosisfrom the expression TUNEL-positive cells. There was an upward trend of cellapoptosis with timedependenc exposed to hyperoxia. Significance differencewas considered when the p.Value was less than0.05.Apoptotic index in hyper-oxia group (Mean±SD)was(26.39±1.45)on the1d,(43.87±1.62)on the3d,and(56.34±1.56)on the7d；Apoptotic index in control group (Mean±SD) was(14.54±1.88) on the1d,(14.68±2.01) on the3d, and (14.45±1.75) on the7d.6.There is a significantly positive correlation between the cell apoptosis and the ratio change of DRP1and OPA1in high oxygen group, apoptosis indexes wasequal to0.725,that was to say that the p.value was less than0.01. Conclusion:1The classical pathologic characters of lung injury were found out in hyperoxiagroup,and it changed obviously with time.2Exposure to hyperoxia led to cellapoptosis of the infant rat’s lung tissue,mechanism was about the gain express-ion of DRP1and the drop expression of OPA1in hyperoxia-induced lung injur-y of premature rats. Mitochondria fusion and split imbalances resulted in frag-mented mitochondria which caused cell apoptosis to participate in hyperoxiclung injury.3The increased ratio change of DRP1and OPA1had time depende-nce with hyperoxia exposure,apoptosis index was along with hyperoxia expos-ure,it was to say that ratio change of DRP1and OPA1had much significantpositive correlation with Apoptotic index of dynamic change.