Protective effect of simvastatin on alveolar type II cells in a rat lung ischemia-reperfusion injury model

Abstract

Objective To evaluate the protective effects on alveolar type Ⅱ cells induced by simvastatin in a rat lung ischemia-reperfusion injury (LIRI) long-term survival model. Methods 108 healthy SD rats were randomly divided into 3 groups: group Ⅰ, the sham group (n =36, no hilar blocking); group Ⅱ, LIRI group ( n = 36, left hilar blocking); group Ⅲ, simvastatin group ( n = 36, animals were orally lung tissue and blood samples were collected at basehne before hilar occlusion and 1 h after ischemia, 4 h,1 day, 3 days and 7 days after reperfusion respectively. The indices were determined as follows: the myeloperoxidase (MPO) activity of lung tissue, the arterial partial pressure of oxygen ( PaO2 ), pulmonary surfactant-C (SP-C) expression and proliferation of AT Ⅱ cells determined by SP-C/proliferating cell nuclear antigen (PCNA) immunofluorensence double staining. Results The rat LIRI long-term survival model was successfully established. As compared with group Ⅱ , the MPO activity, PaO2 and the SP-C mRNA level were significantly reduced in group Ⅲ at the time-points of 4 h and 1 day after reperfusion (P ＜0. 01 respectively). The number of SP-C/PCNA double positive AT Ⅱ cells displayed that as compared with Group Ⅱ , the proliferation of AT Ⅱ cells in group Ⅲ was significantly increased at day 1 after repeffusion.Conclusion AT Ⅱ cells might be a novel target of simvastatin-induced-attenuation of LIRI, in which enhancing the proliferation ability of AT Ⅱ is involved as one of the important mechanisms. Key words: Lung ischemia; Repeffusion injury; Alveolar type Ⅱ cell; Proliferation; Simvastatin