小剂量氯胺酮预处理对大鼠肠缺血再灌注后肾脏血红素加氧酶1表达的影响

摘要

目的 探讨小剂量氯胺酮对血红素加氧酶1(HO-1)在大鼠肠缺血再灌注后肾脏中表达的影响及其可能的保护机制.方法 48只雄性成年SD大鼠随机分为A组(氯胺酮10 mg/kg术前30 min腹腔注射+假手术)、B组(盐水0.2 mL术前30 min腹腔注射+假手术)、C组(氯胺酮10 mg/kg术前30 min腹腔注射+肠缺血再灌注)、D组(盐水0.2 mL术前30 min腹腔注射+肠缺血再灌注)、E组(锌原卟啉Ⅸ5 mg/kg、氯胺酮10 mg/kg术前30 min腹腔注射+肠缺血再灌注)、F组(锌原卟啉Ⅸ5 mg/kg、盐水0.2 mL术前30 min腹腔注射+肠缺血再灌注).小肠缺血再灌注造模组大鼠通过夹闭肠系膜上动脉60 min后松血管夹,于再灌注6 h后取材,测定肾组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;采用链霉亲和素-生物素-过氧化物酶复合物法测定肾组织HO-1的表达和定量;光镜下观察肾脏病理学改变;取外周静脉血测血尿素氮和血清肌酐.结果 与B组比较,各损伤造模组MDA含量显著升高,SOD活力显著下降,血尿素氮和血清肌酐显著升高,HO-1表达上调(P<0.05或P<0.01);C组与D组比较,血尿素氮、血清肌酐、MDA含量均显著降低,SOD活力显著上升,HO-1表达上调(P<0.05);与D组比较,E组、F组血尿素氮、血清肌酐、MDA、SOD值差异无统计学意义;E组与C组比较,血尿素氮、血清肌酐、MDA含量显著升高,SOD活力显著下降,HO-1表达下调(P<0.05).结论 小剂量氯胺酮预处理能减轻肠缺血再灌注后造成的肾脏损伤,这种作用在一定程度上是通过上调HO-1的表达来实现的.%Objective To investigate the effects of low-dose ketamine pretreatment on the expres- sion of heme-oxygenase-1(HO-1) in the kidneys of rats after intestinal ischemia/reperfusion(I/R). Methods 48 male SD rats were randomly divided into group A (10 mg/kg of ketamine given by intraperitoneal intraperitoneal injection 30 min before sham-operation),group B (0.2 mL of saline given by intraperitoneal injection 30 min before sham-operation),group C (10 mg/kg of ketamine given by intraperitoneal injection 30 min before I/R),group D (0.2 mL of saline given by intraperitoneal injection 30 min before I/R),group E (5 mg/kg of zinc protoporphyrin Ⅸ plus 10 mg/kg of ketamine given by intraperitoneal injection 30 min before I/R) and group F (5 mg/kg of zinc protoporphyrin Ⅸ plus 0.2 mL of saline given by intraperitoneal injection 30 min before I/R). The rat model of intestinal I/R injury was constructed by occluding the superior mesenteric artery for 1 h and subsequently reperfused for 6 h. Renal tissues were taken at various intervals for the determination of malondialdehyde (MDA) and superoxide dismutase (SOD). The expression and distribution of HO-1 in renal tissues were detected by strcptavidin-biotin-peroxidase complex method and morphometry computer image analysis. The pathological changes of kidneys were observed under light microscope. The changes of serum crcatinine and blood urea nitrogen in peripheral venous blood were measured respectively. Results When compared with group B,the contents of MDA,serum creatinine and blood urea nitrogen were obviously increased,the activity of SOD was markedly decreased and the expression of HO-1 was up-regulated in all I/R groups (P<0.01 or P<0.05). When compared with group D,the contents of MDA,serum creatinine and blood urea nitrogen were obviously decreased,the activity of SOD was markedly increased and the expression of HO-1 was up-regulated in group C (P<0.05). When compared with group D,there were no significant differences in the contents of MDA,serum creatinine and blood urea nitrogen and the activity of SOD in groups E and F. When compared with group C,the contents of MDA,serum creatinine and blood urea nitrogen were obviously increased,the activity of SOD was markedly decreased and the expression of HO-1 was down-regulated in group E (P <0.05). Conclusion Low-dose ketamine pretreatment may extenuate renal tissue injury caused by in- testinal ischemia/reperfusion though up-regulating HO-1 expression.