PD-1Gene Expression Of The Rats Lung Tissues And Intervention Effect Of Sodium Hydrosulfide In Early Pulmonary Fibrosis Of Acute Lung Injury

Objective To examine the change of PD-1in lung from rats with pulmonaryfibrosis on different times after Oleic acid-treated and to compare with the salinecontrol group，to investigate the role of PD-1protein in the pathogenesis ofexperimental pulmonary fibrosis；To examine cell apoptosis and the change of PD-1expression in the lung of rats with experimental pulmonary fibrosis，to investigate thechanges and significance of apoptosis and PD-1protein in experimental pulmonaryfibrosis；To examine the change of PD-1in lung from Sodium hydrosulfide-treatedrats with Oleic acid-induced pulmonary fibrosis and to compare with the Oleicacid-treated group，in order to explore the effect of Sodium hydrosulfide on PD-1expression in the lung of rats with experimental pulmonary fibrosis.Methods Fifty-four Sprague Dawley（SD）were randomly divided into threegroups: normal control group(C group), Oleic acid-group(M group) and sodiumhydrosulfide-group(I group). Six rats in model group were sacrificed on3,7,14and28days respectively after intravenous injection. The model group and the treatmentgroup were induced to produce pulmonary fibrosis with Oleic acid, while the controlgroup was given with normal saline instead in the same condition.From the secondday the rats in the treatment group were treated with0.1g/L sodium hydrosulfide2mlig,while the other rats with CMC2ml intravenous injection instead. On the seventhday and the twenty-eighth day the Lungs were isolated. Pathological changes in thelungs were evaluated by HE stain and Masson’s trichrome stain. The hydroxyprollineof pulmonary homogenate were measured for evaluation of the degree of pulmonaryfibrosis. The mRNA expression of PD-1was evaluated by RT-PCR quantitativeanalysis,and the immunohistochemical method was used to investigate the change ofPD-1protein. TUNEL was used to detect the change of cell apoptosis. Results1、HE/Masson Staining on the lung tissue The lung of normal control grouprat had no change lesion in every point, but that of M group showed acuteinflammation: there were a great deal of poly-cyte and monocyte infiltration inalveolar space and interstitia, company edema and slight hemorrhage. Alveoli normalstructure was destructed by granulation in severe areas. Alveolitis relieved on the14d,but hemorrhage and edema were still existing, with fibroblast increasing, intervalwidening obviously, collagen deposited and patches of fibrosis. In28d-group,alveolitis did not decreased obviously. Alveola structure was destructed, with masscollagen deposited around neonate blood capillary. Alveolar interval and part ofalveolar space was occupied by collagen and fibrin. Inflammatory cell in interstitiawas mainly lymphocyte infiltration. Alveolitis of M and I group in every phase wasmarkedly severe compared with normal control. While PF was significantly differentfrom normal control just on14and28d. T group has the same tendency as B group;but the degree of alveolitis and pulmonary fibrosis decreased. These results suggestedSodium hydrosulfide may relieve alveolitis and PF induced by Oleic acid in rats.2、HYP concentration HYP concentrations of M group was higher than normalcontrol and I group (P<0.01). But that of M group increased gradually;That of Igroup took on low level, but increased too, HYP was higher than that of control groupand lower than model group（P<0.01or P<0.05）.3、The change of cell apoptisis index in lung tissue The apoptosis index oflung cells on28d in the model group(13.7±3.4)%was higher than that of controlgroup(1.9±0.3)%and treatment group(5.34±1.54)%.There was significant differencebetween the three group (F=79.90,P<0.01)4、PD-1and PD-1mRNA in lung tissue The result of immunohistochemistryand RT-PCR suggested that the expression of PD-1and PD-1mRNA in lung tissueof M group was much higher than that of C and I group,and the difference at everypoint were significant (P<0.01). PD-1concentration and PD-1mRNA of1group was higher than that of normal control, and there was significant difference（P＜0.05）.conclusions1、The apoptosis index of lung cells, PD-1gene and protein was up-regulated in lungtissue of pulmonary fibrosis, which may play an important role in the development ofdisease.2、Sodium hydrosulfide might reduce that the oleic acid induced the rats acute lunginjury and pulmonary fibrosis by suppressing excessive expressing of lung PD-1. PD-1may be a new target molecules of acute lung injury and pulmonary fibrosistreatment.