大鼠骨髓来源MSCs对新生大鼠高氧肺损伤的影响

目的 研究静脉注射大鼠骨髓间充质干细胞(MSCs)对高氧新生大鼠肺损伤的影响.方法 采用贴壁选择法分离、培养、扩增大鼠骨髓来源MSCs,并以5-溴脱氧尿嘧啶核苷(BrdU)进行标记.3 d龄清洁级SD新生大鼠32只,随机分为A、B、C、D四组,每组8只.A、B两组均先将动物置于95%氧环境下,而C、D组则置于空气环境下;7d后,A、C组每只尾静脉注射含5×104MSCs的PBS 50μl,B、D组同时仅给予PBS 50μl,并将大鼠全部置于空气环境下,72 h后处死全部动物,病理学检测肺组织辐射状肺泡计数(RAC),免疫组织化学检测BrdU表达情况,ELASA法检测肺组织匀浆肿瘤坏死因子α(TNFo)、转化生长因子β1(TGFβ1)含量.结果 与空气暴露(C、D)组相比,两高氧(A、B)组RAC值显著降低,TNFα、TGFβ1等显著增加;比较A、B二组,A组在RAC、TNFo、TGFβ1等方面与B组存在显著差异;免疫组化显示A、C两组均可见BrdU阳性细胞表达,且两组间差异有显著性.结论 给新生大鼠静脉注射MSCs后,MSCs可在肺组织定植,其定植水平与动物暴露的环境有关,并对高氧引致的肺损伤具有保护作用,其机制可能与调控肺部微环境等有关.

Intravenous infusion of rat bone marrow-derived mesenchymal stem cells ameliorates hyperoxia-induced lung injury in neonatal rats

OBJECTIVE: To investigate the effect of intravenous infusion of rat bone marrow-derived mesenchymal stem cells (MSCs) against lung injuries in neonatal exposed to hyperoxia. METHODS: Rat bone marrow-derived MSCs were separated, cultured, amplified, and labeled with BrdU. Thirty-two 3-day-old SD rats were randomized into 4 equal groups (groups A, B, C and D), and the rats in groups A and B were exposed to 7-day 95% oxygen, while those in groups C and D were not. In groups A and C, the rats received injection with 5x10(4) MSCs via the tail vein, and those in groups B and D were given PBS only. Seventy-two hours after housing in normal air, all the rats were killed to determine the radial alveolar count (RAC) under light microscope. Immunohistochemistry was used to detect BrdU expression in the lung tissue, where the levels of tumor necrosis factoralpha(TNFalpha) and transforming growth factor beta1 (TGFbeta1) were detected using enzyme-linked immunosorbent assay. RESULTS: Compared to air exposure groups, the levels of TNFalpha and TGFbeta1 in the homogenate of the lungs increased while RACs decreased significantly in the two hyperoxia exposure groups. Groups A and B showed significant differences in the fields of RACs and the levels of TNFalpha and TGFbeta1 in the lung tissue homogenate, and BrdU-positive cells were detected only in the lungs of groups A and C, between which a significant quantitative difference was seen. CONCLUSION: Intravenously injected MSCs may reside in the lungs of neonatal rats, which is subject to influences by the exposure conditions, and the transplanted MSCs may offer effective protection against lung injuries induced by hyperoxia.