Studies On The Effects Of Heat Shock Protein22in Lung Ischemia-Reperfusion Injury

Background and Objective:In the clinical practice of lung transplantation and pulmonary embolism thrombolytic therapy, lung ischemia reperfusion injury associated with high morbidity and mortality can cause acute pulmonary insufficiency. The protective effect of over-expressed HSP22has been clarified in myocardial ischemia reperfusion injury, whether it has a protective effect on lung ischemia-reperfusion has not been studied. In this study, we mainly fous on the protective effect of over-expressed HSP22in mouse lung ischemia-reperfusion injury.Methods:We used Western-Blot to detect HSP22expression level in the lung tissue of transgenic and wild-typed C57BL mice. Twelve HSP22transgenic C57BL mice were randomly divided into2groups: sham operated group and the ischemia/reperfusion group.Twelve wild-typed C57BL mice were grouping in the same method. Then, we established the left lung ischemia-reperfusion injury mice model in situ. After45minutes ischemia and120minutes reperfusion, we tested the arterial oxygen partial pressure, wet to dry weight ratio, malondialdehyde (MDA) level, and observed morphology changes on light microscopy, then evaluated the expression of HSP22by immunohistochemical staining and measured tissue apoptosis on TUNEL method in each group.Results:The result suggested that HSP22protein express level of transgenic mice was significantly2.5times higher than the wild-type mice (P<0.05). Arterial oxygen partial pressure of all four groups were not statistically different (P>0.05). Compared with the WT-SO group, the wet dry weight ratio and index of alveolar damage were significantly increased in the WT-I/R group (P<0.01, P<0.01), similar results were also observed in TG-I/R and TG-SO group (P<0.05, P<0.01). The results indicated that lung ischemia reperfusion injury model was successfully established. Compared with WT-I/R group, the lung wet dry weight ratio, MDA values and the index of alveolar damage of TG-I/R group of mice were significantly decreased (P<0.05, P<0.05, P<0.05). These results suggested that over-expressed HSP22may reduce the lung ischemia reperfusion injury in mouse model. Integrated optical density values of immunohistochemical of HSP22in TG-I/R group was significantly higher than in the TG-SO group (P<0.01),similar results were also observed in WT-I/R group to WT-SO group(P<0.01).It showed that ischemia-reperfusion injury can stimulate the expression of HSP22. The apoptosis result detected by TUNEL method is:the lung tissue cell fluorescence intensity of WT-I/R group was greater than WT-SO group, the analogous results could be attained in TG-I/R group to TG-SO group,whereas,compared to the WT-I/R group,the fluorescence intensity of TG-I/R group was attenuated.It prompted that the cell apoptosis level enhance with lung ischemia reperfusion injury,but,over-expressed HSP22may inhibit injuried cell apoptosis.Conclusion:1Transgenic mice carried HSP22gene was steadily passaged in the F4generation by sequencing, and HSP22protein was over-expressed in the lung tissue of genetically modified mice.2The lung ischemia-reperfusion injury model of transgenic mice carried HSP22gene was successfully established.3Over-expressed HSP22has a protective effect on lung ischemia reperfusion injury, the possible involved mechanism is that HSP22can inhibit lipid peroxidation and cell apoptosis.