TGFβ_1对脓毒症大鼠肝脏MD2表达的影响

Research on the impact of TGFβ_1 on liver MD2 expression in sepsis rats

目的建立大鼠脓毒症模型,观察不同时间点大鼠肝脏髓样分化蛋白2(Myeloid Differential protein-2,MD2)表达情况和NF-κB含量动态变化,并给予外源性TGFβ1干预,探讨TGFβ1对大鼠脓毒症的作用及可能机制,为临床脓毒症的治疗提供思路。方法健康雄性CL级SD大鼠120只随机分为三组:对照组40只,脓毒症模型组40只,TGFβ1干预组40只。按2 h、6 h、12 h、24 h、48 h时间点活杀大鼠取肝脏,HE染色光镜观察肝脏组织形态改变;用ELISA法检测肝脏组织匀浆上清液NF-κB含量;RT-PCR法检测肝脏MD2 mRNA的表达。结果模型组较对照组组织损伤严重,炎症细胞浸润多,伴有出血;TGFβ1组较对照组仍有炎细胞浸润,但较模型组炎症细胞浸润减少,损伤减轻;NF-κB在模型组(6 h、12 h、24 h、48 h)较对照组含量明显增加,差异有统计学意义(P<0.05),并且在24 h达到最高,48 h进入平台期。TGFβ1组(6 h、12 h、24 h)较模型组含量减少,差异有统计学意义(P<0.05);MD2 mRNA在在模型组(6 h、12 h、24 h、48 h)较对照组表达明显增加,差异有统计学意义(P<0.05),并且在24 h表达达到最高,48 h进入平台期;TGFβ1组(12 h、24 h)与模型组比较表达减少,差异有统计学意义(P<0.05)。结论 MD2 mRNA脓毒症时表达明显增加,提示LPS信号转导增强。TGFβ1可能通过抑制LPS的信号转导,减轻炎症反应。

Objective To establish rat model of sepsis, observe the expression of rat liver myeloid differentiation protein-2 （MD2） at different time points and the dynamic changes of the content of NF-κB and give exogenous TGF β1 intervention, to explore the role and the possible mechanism of TGF β1 in rat sepsis model for the treatment of sepsis. Methods One hundred and twenty healthy male SD rats were randomly divided into three groups. The sham group, the sepsis group and the TGF β1 1 treated group （each group 40 rats）. Rats were sacrificed at 2 h, 6 h, 12 h, 24 h and 48 h and liver was taken out. The morphological changes of liver tissue stained with HE were observed under light microscope. The content of NF-κB in the tissue supernatant was detected with ELISA. The expression of liver MD2 mRNA was detected with RT-PCR method. Results The tissue damage of the model group was severer than that of the control group. The infiltration of the inflammatory cell was much more and accompanied with bleeding. Compared with the control group, there was still infiltration of the inflammatory cell in the TGF β1 group, but the infiltration of the inflammatory cell and the tissue damage was milder than that of the model group. The content of NF-κB in the model group （6 h, 12 h, 24 h and 48 h） was obviously increased than that of the control one, and the difference was statistically significant （P 〈 0.05）, and the content at 24 hour was the highest, 48 hour was arrived the platform stage. The content at 5 h, 12 h and 24 h of the TGF β1 j was reduced than that of the model group, and the difference had statistically significant （P 〈 0.05）. The expression of MD2 mRNA at 6 h, 12 h, 24 h and 48 h in the model group was dominantly increased than that in the control one, and the difference was statistically significant （P 〈 0.05）. The expression at the 24 h was the highest, those at the 48 h entered into the platform stage. Compared with the model group, the expression at 12 h and 24 h in TGF β1 was reduced, the difference was statistically significant （P 〈 0.05）. Conclusion In septic model, expression of MD2 is significantly increased, suggesting that LPS signal transduction enhanced. TGF β1 may inhibit LPS, reduce inflammatory reaction.