痢疾志贺菌D_(15)及其L型内毒素致细胞凋亡的研究

Apoptosis induced by endotoxin of Shigella dysenteriae D_(15) and its L-form

目的 :探讨痢疾志贺菌及其L型的致病机制。方法 :将痢疾志贺菌诱导为稳定L型 ,分别制备原菌内毒素和L型内毒素 ,用尾静脉注射法感染小鼠 ,观察小鼠的发病情况 ,并对死亡小鼠进行组织学检查。本实验共分三组 :原菌内毒素组 (A组 ) ,L型内毒素组 (B组 ) ,生理盐水组 (C组 )。结果 :A组对小鼠有较强的致病性 ,以全身中毒症状为主 ;A和B、C组肝细胞凋亡差异均有显著性 (P <0 .0 1) ,但B、C两组差异无显著性 (P >0 .0 5 )。结论 :内毒素可能是痢疾志贺菌致病的主要因素 ,而其L型 ,由于失去细胞壁 ,内毒素丢失 。

Objective:To study the pathogenesis of Shigella dysenteriae and its L forms.Methods: S.dysenteriae were induced into stable L forms and endotoxins of both S.dysenteriae bacterial forms and L forms were prepared.C 57 BL/6J mice were infected through intravenous injection and state of illness were observed.Animals were examined for pathological changes after death.The experiment was divided into 3 groups.Group A was infected with endotoxin of S.dysenteriae original bacterial forms,Group B with endotoxin of S.dysenteriae L forms and group C with normal saline.Results:Pathological changes with systemic intoxication were mainly found in group A.The difference in inducing liver cell apoptosis between group A and group B\,C was very significant( P < 0.01 ).No difference were seen between group B and control group C( P >0.05).Conclusions:Endotoxin may be the main pathogenic substance of S.dysenteriae.Due to the loss of endotoxin together with the cell wall,the pathogenicity of L forms is much weaker than their original forms.