血管活性肠肽和甲泼尼龙对内毒素性休克大鼠肠道Toll样受体mRNA表达的影响

Vasoactive intestinal peptide and methylprednisolone change intestinal Toll-like receptor mRNA expres- sion in rats with endotoxic shock

目的 探讨血管活性肠肽（vasoactive intestinal peptide,VIP）和甲泼尼龙（methylprednisolone,MP）对细菌脂多糖（lipopolysaccharide,LPS）致休克大鼠肠道组织Toll样受体（Toll-like receptor,TLR）2 mRNA和TLR4 mRNA表达的影响.方法 90只SD大鼠,随机分为LPS组（20只）、LPS＋ VIP组（20只）、LPS ＋MP组（20只）、LPS ＋VIP＋ MP组（20只）和对照组（10只）.LPS组尾静脉注射LPS（E Coli O55B5）10 mg/kg;LPS ＋VIP组尾静脉注射LPS 10 mg/kg后注射VIP（5 nmol/kg）；LPS＋ MP组尾静脉注射LPS 10 mg/kg后注射MP 3 mg/kg; LPS＋ VIP＋ MP组尾静脉注射LPS 10 mg/kg后注射VIP 5 nmol/kg＋ MP 3 mg/kg;对照组尾静脉注射等容量生理盐水.分别于注射后6h和24 h处死,留取肠道组织标本,RT-PCR检测肠道TLR2/4 mRNA表达,光镜下观察肠组织病理变化.结果 注射LPS后大鼠肠黏膜坏死脱落,微绒毛结构消失,结缔组织充血,炎性细胞浸润.采用VIP、MP或VIP ＋MP干预组病变较轻.注射LPS6h,LPS组（1.14 ±0.38,1.21 ±0.18）、LPS＋ VIP组（1.17±0.42,1.04±0.38）、LPS＋ MP组（1.16±0.41,1.11±0.34）和LPS＋VIP＋MP组（0.92±0.29,1.01±0.20） TLR2 mRNA与TLR4 mRNA表达均高于对照组（0.32±0.20,0.24±0.17） （P ＜0.01）,LPS组、LPS ＋VIP组、LPS＋ MP组和LPS＋ VIP＋ MP组之间差异无统计学意义（P＞0.05）.注射LPS 24 h后,LPS＋ VIP组（0.63±0.12,0.67 ±0.09）、LPS＋ MP组（0.59 ±0.13,0.64 ±0.09）和LPS＋ VIP＋ MP组（0.52±0.19,0.51 ±0.31）TLR2 mRNA与TLR4 mRNA表达明显低于LPS组（1.04 ±0.38,0.82 ±0.18） （P ＜0.05）.结论 VIP和糖皮质激素的胃肠保护作用与炎症信号TLR2/4 mRNA表达改变有关,在LPS休克6h内,VIP或MP和VIP ＋MP对肠道TLR2/4 mRNA表达影响不明显,24h时VIP、MP和VIP ＋MP可下调TLR2/4 mRNA表达.

Objective To investigate the effect of vasoactive intestinal peptide （VIP） and methylprednisolone （MP） on Toll-like receptor （TLR）2/4 mRNA expression in endotoxin （lipopolysaccharide,LPS） induced shock.Methods Ninety Sprague-Dawley rats were randomly divided into LPS group （n =20）,LPS ＋ VIP group （n =20）,LPS ＋ MP group （n =20）,LPS ＋ VIP ＋ MP group （n =20） and control group （n =10）.LPS group injected intravenously LPS （E Coli O55B5） 10 mg/kg.LPS ＋ VIP group,LPS ＋ MP group and LPS ＋ VIP ＋ MP group were injected intravenously VIP 5 nmol/kg,MP 3 mg/kg and VIP 5 nmoL/kg ＋ MP 3 mg/kg after LPS 10 mg/kg injection.The control group injected normal saline intravenously instead of LPS.The rats were sacrificed at 6 h and 24 h after injection and the intestine samples were collected.Pathological changes of the intestine were observed by microscopy.RT-PCR was used to detect the intestinal TLR2 mRNA and TLR4 mRNA expressions.Results Intestinal mucosa showed edema or necrotic change with structure of the microvilli disappeared after LPS injection.The inestinal lesions in VIP,MP and VIP ＋ MP groups were milder than LPS group.At 6 h after LPS injection,TLR2 mRNA and TLR4 mRNA expressions were significantly up-regulated in LPS group,LPS ＋ VIP group,LPS ＋ MP group and LPS ＋ VIP ＋ MP group （TLR2 mRNA：1.14 ±0.38,1.17 ±0.42,1.16 ±0.41,0.92 ± 0.29;TLR4 mRNA 1.21 ±0.18,1.04 ± 0.38,1.11 ± 0.34,1.01 ± 0.20） compared with the control group （0.32 ± 0.20,0.24 ± 0.17） （P 〈 0.01）.But there was no significant difference between LPS group,LPS ＋ VIP group,LPS ＋ MP group and LPS ＋ VIP ＋ MP group （P 〉 0.05）.At 24 h after LPS injection,TLR2 mRNA and TLR4 mRNA expressions in LPS ＋ VIP group,LPS ＋ MP group and LPS ＋ VIP ＋ MP group （TLR2 mRNA：0.63 ± 0.12,0.59 ± 0.13,0.52 ±0.19;TLR4 mRNA 0.67 ±0.09,0.64 ±0.09,0.51 ±0.13） were significantly lower than LPS group （1.04 ± 0.38,0.82 ±0.18） （P 〈0.01） （P 〈0.05）.Conclusion VIP and/or MP can mitigate intestinal injury induced by LPS shock.The gastrointestinal protection of VIP and glucocorticoids were related to downregulation signaling TLR2 mRNA and TLR4 mRNA expression.But VIP/MP and VIP ＋ MP have no significant effect on expression of intestinal TLR2/4 mRNA until 24 h after LPS shock.