【摘要】 目的:探讨地塞米松(DEX)对大鼠中央髓鞘溶解症(CPM)的预防作用及机理。方法:通过皮下注射长效尿崩停针和腹腔注射2.5%葡萄糖液诱导大鼠低钠血症3 d,第4天腹腔注射1 m o l/L氯化钠液(高渗盐水)快速补钠的方法诱导大鼠CPM模型。DEX早期治疗组大鼠在注射高渗盐水同时肌注5 m g/kg DEX;DEX延迟治疗组大鼠在注射高渗盐水后24 h肌注5 m g/kg DEX;生理盐水治疗组大鼠在注射高渗盐水同时肌注生理盐水;另设正常对照组。观察大鼠脑组织脱髓鞘病变发生情况;测定脑内伊文思兰(EB)的含量变化;W estern b lot印迹法测定脑内一氧化氮合酶(iN-OS)的表达变化。结果:通过诱导低钠血症、快速补钠的方法成功建立了大鼠CPM模型。DEX早期治疗组、DEX延迟治疗组、生理盐水治疗组3组大鼠在快速补钠后0 h时点,脑内EB含量与正常对照组无明显差异(P>0.05)。生理盐水治疗组大鼠在快速补钠后6 h,脑内EB含量比0 h时点明显增加(P<0.05),24 h达高峰,同时脑内iNOS在快速补钠后3 h开始表达增强,36 h仍呈较强表达,脱髓鞘发生率为66.7%。DEX早期治疗组大鼠快速补钠后脑内EB含量及iNOS表达,均较同时点生理盐水治疗组明显下降,未见明显脱髓鞘病变。DEX延迟治疗组脱髓鞘病变发生率为75%,与生理盐水治疗组无明显差异(P>0.05)。结论:早期应用DEX能够通过保护血脑屏障和抑制脑内iN-OS表达,起到预防CPM的作用。更多还原

【Abstract】 Objective: To explore the effect and mechanism of dexamethasome（DEX） in the prevention of central pontine myelinolysis（CPM） in rats.Methods: Hyponatremia was induced in rat by subcutaneous injection of Vasopressin Tannate and intraperitoneal injection of 2.5% dextrose in water for 3 d,the rats of Group A received a bolus of 1mol/L NaCl（2ml/kg） and DEX（5mg/kg） simultaneously at the 4^th day;the rats of Group B were treated with DEX after 24 h of the injection of 1mol/L NaCl;the rats in Group C received a bolus of 1mol/L NaCl and saline simultaneously;Group D was the control group.The demyelinative lesions were evaluated by myelin staining.The Evans blue（EB） contents of brain were detected to evaluate the blood-brain（-barrier） permeability after rapid correction of hyponatremia.The expression of inducible nitric oxide synthase（iNOS） in brains was evaluated by Western blotting.Results: CPM was induced successfully in rats.The EB contents of Group A,B and C had no significant difference at 0 h after injection of hypertonic saline compared with Group D.The EB contents of Group C began to increase significantly at 6 h after injection of hypertonic saline,peaked at 24 h;the expression of iNOS in brains began to increase after 3 h after the rapid correction of hyponatremia.The rate of morbidity in Group C was 66.7%.The demyelinative lesions were rarely seen in Group A,the EB contents of brain decreased significantly compared with Group C at the same time point（P<0.05）,the iNOS expression was also inhibited.DEX could not prevent the attack of CPM at Group B,the rate of morbidity（75%） had no significant difference compared with Group C（P>0.05）.Conclusion: Early treatment with DEX can protect blood-brain-barrier and inhibit the expression of iNOS to prevent the attack of CPM.更多还原