脓毒症小鼠肺组织瘦素水平及其它相关酶活性的研究

Leptin level in lungs of septic mice and its relationship with other related enzymes

目的研究脓毒症对肺组织瘦素水平及相关酶活性的影响,探讨瘦素在急性炎症反应中的作用。方法建立小鼠盲肠结扎致脓毒症模型,采用放射免疫分析法和分光光度分析法分别检测肺组织匀浆液中瘦素及髓过氧化物酶(MPO)、谷胱甘肽-S转移酶(GST)、黄嘌呤氧化酶(XOD)、超氧化物歧化酶(SOD)等4种与自由基合成、解毒和嘌呤生成代谢相关的酶的水平,同时以HE染色方法观察肺组织病理组织学改变。结果肺组织匀浆液中瘦素水平(19.58±7.73)μg/L明显低于假手术对照组(29.07±8.27)μg/L,腹腔内注射瘦素(0.1mg/ml)后6h可见脓毒症小鼠肺内瘦素水平上升(33.62±11.54)μg/L,而吲哚美辛给药(2mg/kg)却无效。同时,还发现瘦素保护组可恢复肺组织MPO活性(17.74±8.96)vs脓毒症组(30.70±4.37)U/g、降低肺GST活性(26.50±8.73)vs假手术组(70.11±20.44)kU/g、升高肺XOD活性(0.14±0.03)vs假手术组(0.12±0.04)U/g,但对肺SOD无显著影响。肺组织病理切片HE染色显示,与假手术组相比,瘦素保护组肺水肿减轻、炎性分泌物减少;吲哚美辛对肺组织的影响与瘦素相比并不一致。结论脓毒症发生后6h肺组织瘦素水平显著下降,伴随MPO、GST、XOD的显著改变。经腹腔内注射瘦素后可恢复肺组织瘦素水平,同时改善和调节上述酶活性于正常或接近正常水平,而吲哚美辛的保护作用与瘦素水平无关。

Objectives To study the effect of sepsis on leptin levels and related enzymes in lungs of mice, and to explore the role of leptin in acute inflammation. Methods Sepsis model of mice was established by cecum ligation and perforation. Radioimmunoassay was used for determining leptin and spectrophotometry assay was used for measuring levels of four enzymes related to synthesis of free radicals, detoxication and metabolism of purine, including myeloperoxidase （MPO）, glutathion-S-transferase （GST）, xanthine oxidase （XOD） and superoxide dismutase （SOD）, in lungs homogeniate. Hematoxylin-eosin stain was used to observe the histopathologic changes of lungs. Results Compared with sham operation group （29.07±8.27 /μg/L）, leptin levels in lungs of sepsis mice were significantly lower （19.58±7.73μg/L）. Six hours after leptin injection （0.1 mg/ml, ip）, leptin levels in lungs of sepsis mice significantly increased （33. 62 ± 11. 54 ng/ml）, while indomethacin injection （2 mg/kg, ip） had no such effect. Moreover, leptin injection could recover MPO activity （17.74±8.96 vs sepsis nice 30.70±4.37 U/g）, decrease GST activity （26.50± 8.73 vs sham operation 70.11±20.44 kU/g） and increase XOD activity （0.14±0.03 vs sham operation 0.12±0. 04 U/g） in lungs, but it could not influence SOD activity. Histopathologic investigation of lungs slices found that pulmonary edema was relieved and inflammatory secretion decreased in leptin injection group （vs sham operation group）, but indomethacin injection had different influence from it. Conclusions Six hours after sepsis, leptin levels in lungs decreased significantly, accompanied by significant increase in MPO, GST and XOD activities. Leptin injected intraperitoneally could recover leptin level in lungs, improve and modulate levels of aforementioned enzymes to normal or nearly normal levels, while indomethacin protection had no relation with leptin.