地塞米松改善脂多糖诱导的炎症反应及足细胞损伤

Dexamethasone Ameliorates Lipopolysaccharide-induced Inflammatory Reaction and Podocyte Injury

目的 Nephrin在维持肾小球裂孔隔膜结构的完整性上起关键作用。本文观察地塞米松对脓毒症小鼠及体外培养足细胞nephrin磷酸化水平的影响,探讨其改善足细胞损伤的机制。方法脂多糖制备脓毒症小鼠模型,设正常对照组、脓毒症组、地塞米松治疗组。检测24 h尿蛋白和血清超敏C反应蛋白、白介素-6、降钙素原。RT-PCR、Western blot法检测nephrin mRNA的表达及磷酸化水平。体外培养小鼠永生化足细胞,分别给予脂多糖或地塞米松干预,TUNEL法检测足细胞凋亡,MTT法测定足细胞活力,并检测足细胞nephrin mRNA及磷酸化水平。结果在脓毒症小鼠实验中,脓毒症组24 h尿蛋白、血清超敏C反应蛋白、白介素-6、降钙素原水平升高,nephrin mRNA表达及磷酸化水平降低,地塞米松可改善脓毒症鼠尿蛋白及炎症指标,维持nephrin mRNA的表达及磷酸化水平。在体外培养的足细胞中,脂多糖诱导足细胞的凋亡,降低足细胞的活力,降低nephrin mRNA表达及磷酸化水平;而地塞米松明显减少足细胞的凋亡,刺激足细胞的活力,上调nephrin mRNA的表达及磷酸化水平。结论地塞米松拮抗脂多糖引起的炎症反应,改善nephrin的磷酸化水平,保护足细胞。

Objective Nephrin plays a key role in maintaining the structure of the slit diaphragm in the glo- merular filtration barrier. In this paper, we observed the effect of dexamethasone （ Dex ） on the level of nephrin phosphorylation in sepsis mice and euhured podocytes in vitro , and investigated the mechanism by which Dex amel- iorates podoeyte injury. Methods Mice were injected with lipopolysaecharide （LPS） to induce a sepsis model and randomly divided into three groups ： control group （ n = 10 ）, sepsis model group （ n = 10 ）, sepsis ＋ Dex treated group（ n = 10）. The levels of 24-hour urinary protein （24h UP）, serum hypersensitive c-reactive protein （hs- CRP）, interleukin-6 （IL-6） , and proealeitonin （PCT） were measured. The mRNA expression and phosphorylation of nephrin were detected by fluorescent quantitative reverse transeription-polymerase chain reaction （RT-PCR）and Western blotting respectively. Immortalized mouse podoeyte cells were cultured in vitro , intervened with LPS or Dex, while podoeyte apoptosis and viability were measured by TUNEL staining and MTT methods, respectively. Re- sults In sepsis mice, the levels of 24h UP, hs-CRP, IL-6, PCT were elevated while the mRNA expression and phosphorylation of nephrin were decreased. Dex significantly ameliorated proteinuria and inflammation indexes, but maintained the mRNA expression and phosphorylation level of nephrin. In cultured podocytes, LPS induced the ap- optosis of podoeytes, decreased the viability of podocytes, and down-regulated the mRNA expression and phosphoryl- ation of nephrin. However, Dex obviously inhibited podocyte apoptosis, stimulated podocyte viability, and up-regu- lated the mRNA expression and the phosphorylation of nephrin. Conclusion Dex can reverse LPS-indueed inflamma- tory reaction, improve nephrin phosphorylation, and protect podoeytes from injury.