桦木酸通过抑制P38 MAPK磷酸化减轻横纹肌溶解致急性肾损伤

Betulinic Acid Ameliorates RhabdomyolysisInduced Acute Kidney Injury by Inhibiting the Phosphorylation of P38 MitogenActivated Protein Kinases in Rats

目的:探讨P38丝裂酶原活化蛋白激酶(mitogenactivated protein kinases,MAPK)在横纹肌溶解致急性肾损伤中的变化和作用,以及桦木酸的干预效应。方法:将40只Wistar大鼠随机分为五组:正常对照组(C,n=8),AKI组(A,n=8),AKI+桦木酸组(AB,n=8),AKI+SB203580组(AS,n=8),AKI+桦木酸+SB203580组(ABS,n=8)。通过后肢甘油肌注法建立横纹肌溶解致急性肾损伤模型。AB、AS组分别给予腹腔注射桦木酸和SB203580,ABS组两药合用。24小时后,生化分析仪检测血肌酐、尿素、肌酸激酶水平;HE染色观察肾脏病理变化;Western blot法检测肾组织pP38 MAPK、P38 MAPK和cleaved Caspase-3表达;ELISA法检测肾组织TNF-α和IL-6水平。结果:甘油肌注后,肾脏出现急性损伤,pP38/P38比值升高。BA和SB203580干预后pP38/P38比值降低。在本实验剂量下,BA干预组的肾功能指标、病理损伤评分、细胞凋亡、IL-6水平和pP38/P38比值均低于SB203580干预组,而TNF-α水平基本一致。BA+SB203580干预组的总体治疗效果与BA组相比无明显差异。结论:在横纹肌溶解致急性肾损伤中,P38 MAPK被激活,使用SB203580抑制P38 MAPK的磷酸化可降低肌酐尿素水平,抑制肾脏炎症反应,减轻肾病理损伤和细胞凋亡。桦木酸至少部分通过抑制P38 MAPK磷酸化发挥肾脏保护作用。

Objective:To investigate the change and effect of P38 MAPK in rhabdomyolysis-induced acute kidney injury(AKI)and the interfered effect of betulinic acid(BA).Methods:40 Wistar rats were randomly divided into 5 groups:control group(C),group AKI(A),group AKI+BA(AB),group AKI+SB203580(AS),group AKI+BA+SB203580(ABS).The experimental model of rhabdomyolysis-induced AKI was established by injecting 50%glycerin intramuscular into the hind limbs.Group AB,AS and ABS were administered intraperitoneally with BA and SB203580 separately or together.24 hours after glycerin injection,the venous blood and kidney samples were taken.The serum creatinine(CR),blood urea nitrogen(BUN)and creatine kinase(CK)were detected with automatic biochemistry analyzer.The expression of pP38 MAPK,P38 MAPK and cleaved caspase-3 in kidney were assayed by Western Blot.The pathological changes were examined by H&E staining.The levels of TNF-αand IL-6 in kidney were measured by ELISA.Results:Glycerin injection induced acute injury and pP38/P38 ratio was higher in the kidney,which were ameliorated by administration of BA and SB203580.In the dosage of this experiment,BA had better curative effect on renal function,kidney injury score,apoptosis rate and IL-6 level than SB203580.But the inhibition of P38 phosphorylation of SB203580 was stronger than BA.The influence on TNF-αof both drugs were similar.Generally,combined treatment of the two drugs had no significant difference with BA alone.Conclusion:In rhabdomyolysis-induced AKI,P38 MAPK was activated.Inhibition of P38 phosphorylation by SB203580 could reduce the level of Cr and BUN,suppress renal inflammation,alleviate the pathological damage and apoptosis.BA played a renoprotective role at least partially through inhibit ing the phosphorylation of P38 MAPK.