生长激素加重内毒素腹腔感染大鼠肺毛细血管损伤：循环中性粒细胞核因子—κB活性增加

目的:探讨生长激素对大鼠内毒素腹腔感染时循环中性粒细胞核因子-κB(NF-κB)活性及肺损伤的影响.方法:凝胶迁移率实验(EMSA)检测循环中性粒细胞NF-κB的活性;免疫印迹(Western blot)检测循环中性粒细胞I-κB水平;髓过氧化物酶(MPO)水平和伊文氏蓝(Evan’Blue)方法测定肺组织中性粒细胞浸润及肺毛细血管通透性.结果:大鼠内毒素腹腔感染时循环中性粒细胞中I-κB水平降低,NF-κB活性增加.应用生长激素可进一步降低I-κB水平并增加 NF-κB活性.感染时肺组织中性粒细胞浸润增多,肺毛细血管通透性增加,合并应用生长激素则明显增加肺组织中性粒细胞浸润和肺毛细血管损伤.结论:感染时应用生长激素可加重肺组织的损伤,其可能机制是感染时应用生长激素提高循环中性粒细胞中NF-κB活性和促进肺组织中性粒细胞浸润.

Growth hormone increases lung microvascular injury in lipopolysaccharide peritonitis rats: possible involvement of NF-kappaB activation in circulating neutrophils

AIM: To investigate the effects of growth hormone (GH) on NF-kappaB activity in neutrophils and neutrophils-mediated organ injury induced by lipopolysaccharide (LPS) in rats. METHODS: Male Wistar rats challenged with or without LPS (5 mg/kg) were treated with varied doses of GH (0.5, 1.0, and 2.0 mg/kg) for 2 or 4 h. NF-kappaB activities in circulating neutrophils were measured with electrophoretic mobility shift assays (EMSA), and I-kappaB levels in circulating neutrophils were detected by Western blot. Lung neutrophils sequestration and lung microvascular permeability were measured at 4 h after LPS challenge. RESULTS: Circulating neutrophils in LPS challenged rats had increased NF-kappaB activity and decreased I-kappaB level as compared with controls. GH dramatically increased NF-kappaB activity and I-kappaB degradation induced by LPS challenge in neutrophils. Also, subsequently, GH treatment increased lung neutrophils sequestration and lung microvascular injury induced by LPS. CONCLUSION: These results suggest that treatment of GH is harmful, instead of beneficial, to LPS-induced organ injury. Increased neutrophils' NF-kappaB activity and lung neutrophils sequestration are critical in vivo mechanisms mediating GH action on LPS-induced organ injury.