The Protection And Mechanism Of MiR-132 In Septic Mice With Lung Injury

Objective:To observe the dynamic changes of microRNA-132(mi R-132) expression in lung tissue on septic mice with lung injury, and to observe the effect of transfected mi R-132 in vivo on expression of cholinesterase and the inflammation after sepsis induced lung injury in mice. To explore the protective effect and regulatory mechanism of mi R-132 in septic mice with lung injury.Method:1. Healthy male SPF level of BABL/c mice were successfully to establish the septic lung injury model by cecal ligation and puncture(CLP). The degree of lung injury was detected by lung pathological slices, the expression of TNF- alpha, IL-1beta and IL-6 in the bronchoalveolarlavagefluid(BALF) was detected by ELISA,calculate the lung wet dry ratio, the expression changes of mi R-132 of lung tissue was detected by RT-q PCR, the acetylcholinesterase(Ach E) protein expression was detected by western blot and the Ach E activity in BALF was detected by T-CHE kit.2. We selected the in vivo-jet PEITM to mediated the transfection of mi R-132 in vivo by tracheal instillation, then establish the septic lung injury model by CLP. 24 hours after transfection, Take the BALF in the left lung lavage, the expression of TNF- alpha, IL-1 beta and IL-6 in the BALF was detected by ELISA, The degree of lung injury was detected by lung pathological slices, calculate the lung wet dry ratio,the expression changes of mi R-132 of lung tissue was detected by RT-q PCR, the Ach E protein expression was detected by western blot and the Ach E activity in BALF was detected by T-CHE kit.Results:1. The septic lung injury model was successfully built by cecal ligation and puncture, the lung pathological slices showed lung injury was began on 6h after the CLP, the lung injury severity increases with time, 24 h after the CLP, the lung injury was the most severe. The pulmonary edema was aggravated gradually after the CLP,lung wet dry ratio was increased with the time, the pulmonary edema was the mostsevere on 24 h later, then reduced gradually.The inflammatory cytokines in BALF were increased gradually with time after CLP, the expression of TNF-α reached the peak at 12 h and 24 h, IL-1β and IL-6 reached the peak at 24 h, then began to drop gradually.2. The expression of mi R-132 was up-regulation in the sepsis induced lung injury, after the CLP, the level of mi R-132 in lung tissue was increased gradually, the expression reached peak at 12 h and 24h(13.27±1.21 and 14.31±1.24 times), then decreased.3. The expression of mi R-132 in lung tissue was significantly up-regulation by intratracheal instillation of vivo-jet PEITMmediated mi R-132 transfection, the expression reached the peak at 24 h after transfection. Lung pathological slices showed the degree of lung injury of transfected group was reduced compared with other groups, the pulmonary edema and the inflammatory cytokines of transfected group was reduced also. So up-regulated the expression of lung mi R-132 can reduce inflammatory response in septic mice with lung injury.4. The expression of Ach E protein in lung tissues and the activity of Ach E in BALF increased with time after CLP. But the expression of Ach E protein in lung tissues and the activity of Ach E were inhibited by up-regulation of lung mi R-132. It is suggested that mi R-132 can inhibit the expression of Ach E protein expression,reduced the activity of Ach E through improving the cholinergic anti-inflammatory activity.Conclusion:Up regulation of lung mi R-132 can reduce the degree of lung injury in septic mice, the protective mechanism of mi R-132 in septic mice with lung injury was for its suppression of Ach E and enhancement of the cholinergic anti-inflammatory pathway in sepsis-induced lung injury.