烧伤延迟复苏加重肠黏膜屏障功能损害的机制研究

Mechanism of delayed resuscitation in promoting loss of intestinal mucous membrane barrier function after rats scalding

目的:研究大鼠严重烧伤后延迟复苏对肠黏膜屏障功能的影响,探讨中性粒细胞浸润在肠黏膜屏障功能损害中的作用及可能机制. 方法:Wistar大鼠40%TBSAⅢ度烫伤,分立即复苏组和延迟复苏组,于伤后不同时相点检测血中D-乳酸、二胺氧化酶(DAO)及肠黏膜组织髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)和丙二醛(MDA)含量;肠黏膜组织石蜡切片黏膜上皮细胞凋亡原位检测. 结果:延迟复苏组各时相点血中D-乳酸含量明显高于立即复苏组(P<0.05),肠黏膜组织局部MPO活性显著升高(与立即复苏组比较,P<0.01)伴SOD活性降低和MDA含量升高.两组血DAO含量以伤后6 h最高,延迟复苏组约为立即复苏组的两倍(1.40±0.20 vs 0.78±0.19,P<0.01),伤后24 h比较,二者仍具统计学差异.各时相点两组动物均能检测到TUNEL染色阳性肠黏膜上皮细胞,以伤后12 h 为凋亡高峰,延迟复苏组各时相点凋亡率均显著高于立即复苏组. 结论:烧伤延迟复苏加重肠黏膜屏障功能损害,黏膜上皮细胞坏死和凋亡共同构成早期屏障功能损害加重的病理学基础,而组织局部中性粒细胞浸润增强可能在其中起重要作用.

AIM: To investigate the effect of delayed resuscitation on intestinal mucous membrane barrier function and its relationship with neutrophil infiltration of local tissue after rats scalding. METHODS: Rats with 40% full-thickness scald burn were randomly divided into two group: immediately resuscitation group (IR group) and delayed resuscitation group (DR group). The content of D-lactate, diamine oxidase (DAO) in plasma and myeloperoxidase (MPO), superoxide dismutase (SOD) and malondialdehyde (MDA) in intestinal mucous tissue were determined at different time points after bum. Apoptosis of mucous epithelial cells were identified by terminal deoxynucletidyl-transferase mediated dUTP-biotin nick end labeling (TUNEL) histochemical methods. RESULTS: The contents of D-lactate in plasma in DR group were much higher than those of IR group (P<0.01 or 0.05), MPO activity in intestinal mucous tissue of DR group were dramatically increased accompanying with decrease of SOD activity and increase of MDA contents. Herein, we found a close correlation between the contents of D-lactate and activity of MPO. Meanwhile, we also found an increase of the activity of DAO in plasma and number of TUNEL positive staining epithelial cells in DR group. CONCLUSION: Delayed resuscitation promotes the loss of intestinal mucous membrane barrier function due to the increase of both cell necrosis and cell apoptosis, which may be related to increased neutrophil infiltration in local tissue.