Study On The Treatment And Mechanism Of Hyperoxia-induced Aucte Lung Injury In Neonatal Rats

PartⅠThe effect of bone marrow mesenchymal stem cells on the hyperoxia-induced acute lung injury in neonatal rats【Objective】To investigate the effect of MSCs on the hyperoxia-induced acute lung injury in neonatal rats.【Methods】MSCs of rats were resuscitated in vitro,A model of hyperoxia-induced acute lung injury in neonatal rats was established by exposed to 95%O2 for 7 days.After the model was established ,40 rats were divided randomly into the treated group and the control group.The 20 treated group were injected 1×105 MSCs via the tail vein,the 20 control group were injected PBS only via the tail vein .The20 normal rats were blank group.Lung tissues were collected for doing pathological section and assessing the extent of lung edema (W/D)and the level of myeloperoxidase(MPO)after 24 and 48h.【Results】The gross and micrographic injury of lung was milder in treated group than that in control group at 24 and 48h. The levels of W/D and MPO in treated group were lower than those in control group(P <0.05) at 24 hour.The levels of W/D and MPO in treated group were much lower than those in control group(P <0.01) at 48 hour.【Conclusion】MSCs can offer effective treatment against acute lung injury induced by hyperoxia in neonatal rats. PartⅡThe expression of Toll-like receptor2 in hyperoxia-induced acute lung injury in neonatal rats【Objective】To observe the expression of Toll-like receptor2(TLR2) in hyperoxia -induced acute lung injury in neonatal rats in order to investigate the mechanism of hyperoxia-induced aucte lung injury.【Methods】A model of hyperoxia-induced acute lung injury in neonatal rats was established by exposed to 95% O2 for 7 days.The 8 hyperoxia-induced acute lung injury rats were experimental group and the 8 normal neonatal rats were control group. The expression of TLR2 was detected by immunohistochemistry,real-time PCR and western blot. The levels of TNF-αand IL-1βin serum were measured by ELISA.【Results】Immunohistochemistry showed that TLR2 protein mostly expressed in alveolar epithelial cells and macrophages. The expression of TLR2mRNA and protein were upregulated in the experimental group lung tissue compared with the control group .The levels of TNF-αand IL-1βin serum in the experimental group were significantly higher than those in the control group. 【Conclusion】The expression of TLR2mRNA and protein were upregulated during hyperoxia-induced acute lung injury in neonatal rats. TLR2 participates in the pathophysiology of hyperoxia-induced acute lung injury in neonatal rats.