高糖状态下右美托咪定预处理对大鼠肾缺血再灌注损伤影响的机制探讨

The mechanism of preconditioning on renal ischemia reperfusion injury in rats and the effects of dexmedetomidine under high glucose condition

目的探讨高糖状态下右美托咪定(Dex)预处理对大鼠肾缺血再灌注损伤影响的机制。方法 2014年10月—2015年6月于武汉大学人民医院中心实验室进行实验,成年雄性SD大鼠36只随机分为:假手术组(NGSham)、缺血再灌注组(NG-I/R)、右美托咪定预处理组(NG-Dex)、高糖假手术组(HG-Sham)、高糖缺血再灌注组(HGI/R)、高糖右美托咪定预处理组(HG-Dex)各6只。除假手术组外其余各组均制备肾缺血再灌注模型,Dex预处理组于缺血前30 min腹腔注射Dex 50μg/kg。采用原位末端转移酶标记(TUNEL)法测定细胞凋亡,Western blot法检测肾脏Bax、Bcl-2、蛋白激酶B(AKT)、磷酸化AKT(p-AKT)。结果与NG-Sham组比较,NG-I/R组可见到明显的肾小管损害,包括肾小管扩张,肾小管上皮细胞肿胀,固有核,炎性肾小管坏死,凋亡指数、Bax、P-AKT均增高,而Bcl-2降低(F=6.667、469.889、1.200、0.791、0.499,P<0.05);与NG-I/R组比较,NG-Dex组结构较为正常,可见到正常的肾小管结构和肾小管细胞,凋亡指数、Bax降低,而p-AKT,Bcl-2升高(F=59.333、27.667、0.028、0.034、0.024,P<0.05);HG-I/R组、HG-Dex组的细胞破坏程度、凋亡指数、Bax、P-AKT分别高于对应的NG-I/R组、NG-Dex组,而Bcl-2低于对应组(F=66.000、497.556、1.227、0.824、0.523,P<0.05);HG-I/R组、HG-Dex组之间凋亡指数、P-AKT无明显差异(P>0.05)。结论 Dex对正常肾缺血再灌注损伤具有保护作用,但这种作用在高糖环境中被削弱,可能与通过p-AKT、调控Bcl-2及Bax的表达,进而增加肾I/R损伤有关。

Objective To investigate the mechanism of preconditioning on renal ischemia reperfusion injury in rats and the effects of dexmedetomidine under high glucose condition .Methods From October 2014 to June 2015 , in the Central Laboratory of Renmin Hospital of Wuhan University , 36 adult male SD rats were randomly divided into：sham operation group （NG-sham）, ischemia and reperfusion group （NG-I/R） and dexmedetomidine preset treatment group （NG-Dex）, high glu-cose sham operation group （ HG-Sham） , sugar ischemia again perfusion group （ HG-I/R） , high glucose dexmedetomidine pre-set treatment group （HG-Dex） with 6 rats in each group.The renal ischemia reperfusion model was made in all groups except the sham operation group , Dex pretreatment group was injected Dex 50μg/kg 30 min before ischemia .Cell apoptosis was de-termined by in situ terminal transferase labeling （TUNEL） method.Blot Western method was used to detect Bax , Bcl-2, pro-tein kinase B （AKT） and phosphorylated AKT （p-AKT）.Results Compared with NG Sham group, NG-I/R group can be seen in tubular damage obviously , including renal tubular expansion , renal tubular epithelial cell swelling , nucleus proprius and inflammatory renal tubular necrosis , apoptosis index, Bax, p-AKT were increased, Bcl 2 was decreased （ F =6.667, F =469.889, F =1.200, F =0.791, F =0.499, P 〈0.05）;compared with NG I/R group, NG-Dex group structure was normal, visible to the normal structure of renal tubule and renal tubular cells , apoptosis index and Bax decreased , and p-AKT, Bcl-2 increased （ F =59.333, F =27.667, F =0.028, F =0.034, F =0.024, P 〈0.05）; HG-I/R group, HG-Dex cell damage the degree of apoptosis index , Bax, p-AKT were higher than that of NG I/R group and NG-Dex group, the Bcl 2 lower than that of the corresponding group （ F =66.000, F =497.556, F =1.227, F =0.824, F =0.523, P 〈0.05）; HG-I/R group, HG group＇ s p-AKT Dex apoptosis index had no significant difference （ P 〉0.05）.Conclusion Dex has a protective effect on normal renal ischemia-reperfusion injury , but this effect is impaired in a high glucose environment , which may be related to the expression of p-AKT, regulation of Bcl-2 and Bax, and increased renal I/R damage.