比较不同剂量地塞米松对小鼠脓毒症致急性肾损伤的保护作用

The protective effect of different doses of dexamethasone on acute kidney injury induced by sepsis in mice

【摘要】目的比较不同剂量地塞米松（DEX）对脓毒症导致的急性肾损伤（AKl）的影响。方法健康雄性昆明小鼠130只，按随机数字表法均分为假手术组、脓毒症模型组和DEX生理剂量组（O．12mg／kg）、应激剂量组（1．2mg／kg）、大剂量组（12mg／kg）。采用盲肠结扎穿孔术（CLP）制备脓毒症模型，分别在术后24h、48h观察肾组织病理学变化，免疫组化法检测肾组织糖皮质激素受体-α（GR-α）蛋白表达水平，实时荧光定量聚合酶链反应（PCR）检测肾组织GR-α、核转录因子一κB（NF—κB）的mRNA表达水平，酶联免疫吸附试验（EusA）测定血浆肿瘤坏死因子-α（TNF-α）、白细胞介素一1p（IL_1p）的含量。结果与假手术组比较，脓毒症模型组小鼠肾小管病理损害严重；。肾组织GR-α蛋白和mRNA表达明显降低，NF—κBmRNA表达及血浆TNF-α、IL-1B水平均明显升高。与脓毒症模型组比较，各剂量DEX组肾小管病理损害不同程度减轻；肾组织GR-α蛋白和mRNA表达均明显升高，NF—κBmRNA表达和血浆TNF-α、IL-1B水平均明显降低，其中以DEX生理剂量组作用尤佳[AKI评分（分）24h：1．480±0．334比3．040±0．517，48h：1．840±0．167比3．400±0．400；GR-α蛋白（A值）24h：0．102±0．009比0．088±0．005，48h：0．103±0．008比0．085±0．006；GR—dmRNA24h：0．0400（O．0300，0．0400）比0．0100（O．0093，0．0100），48h：0．0350（0．0300，0．0475）比0．0100（0．0010，0．0138）；NF—κBmRNA24h：0．009±0．001比0．012±0．000，48h：0．011±0．000比0．013±0．001；TNF-α（ng／L）24h：105．84±3．84比135．52±4．49，48h：111．35±3．67比141．22±4．46；IL-1B（ng／L）24h：45．71±2．93比64．12±3．62，48h：57．04±3．04比74．87±3．67；P〈0．05或P〈0．01]。结论生理剂量DEX可以通过上调肾组织中GR一仅表达，减轻脓毒症引起的肾组织损伤，其作用明显优于大剂量DEX。

Objective To investigate the effect of different doses of dexamethsone （DEX） on sepsis induced acute kidney injury （AKI）. Methods One hundred and thirty healthy male Kunming mice were randomly divided into sham group, sepsis group, physiological-dose DEX group （0.12 mg/kg）, stress-dose DEX group （1.2 mg/kg）, and high-dose DEX group （12 mg/kg）. The sepsis model was reproduced by cecal ligation and puncture （CLP） method. Histopathological changes in the kidney were observed at 24 hours and 48 hours after CLP. The expressions of glucocortieoid receptor-α （GR-α） in the kidney were detected by immunohistochemistry. The levels of GR-α mRNA and nuclear factor-κB （NF-κB） mRNA were determined by real-time polymerase chain reaction （PCR）. The levels of tumor necrosis factor-α （TNF-α） and interleukin-1β （IL-1β） in the plasma were measured by enzyme linked immunosorbent assay （ELISA）. Results Compared with sham group mice, sepsis mies showed serious impairment in renal tubules. The mRNA and protein expression of GR-αwere decreased, and NF-κB mRNA, plasma TNF-α and IL-I± were elevated. Compared with sepsis group, the histopathologieal changes in the kidney were mitigated with different levels in groups treated with different doses of DEX. GR-α protein and mRNA were up-regulated, NF-κB mRNA and plasma TNF-α, IL-1β were down-regulated obviously. The best effect could be seen in physiological DEX group [AKI score： 24 hours 1.480 ± 0.334 vs. 3.040 ± 0.517, 48 hours 1.840 ± 0.167 vs. 3.400 ± 0.400; GR-ct protein （A value） ： 24 hours 0.102 ± 0.009 vs. 0.088 ± 0.005, 48 hours 0.103 ± 0.008 vs. 0.085 ± 0.006; GR-ct mRNA： 24 hours 0.0400 （0.0300, 0.0400） vs. 0.0100 （0.0093, 0.0100）, 48 hours 0.0350 （0.0300, 0.0475） vs. 0.0100 （0.0010, 0.0138）; NF-κB mRNA： 24 hours 0.009 ± 0.001 vs. 0.012 ± 0.000,48 hours 0.011 ± 0.000 vs. 0.013 ±0.001 ; TNF-a （ng/L） ： 24 hours 105.84 ± 3.84 vs. 135.52 ± 4.49, 48 hours 111.35 ± 3.67 vs. 141.22 ± 4.46; IL-113 （ng/L）： 24 hours 45.71 ± 2.93 vs. 64. 12 ± 3.62, 48 hours 57.04 ± 3.04 vs. 74.87 ± 3.67; P〈0.05 or P〈0.011. Conclusions DEX given in physiological-dose could increase renal GR-α level and alleviate the sepsis induced kidney injury. The protective effect was much better than that of high dose DEX.