肢体远隔缺血预处理对大鼠肌皮瓣缺血再灌注时血清NO和内皮素含量的影响

Effects of limb remote ischemic preconditioning on the levels of serum NO and ET following myocutaneous flap ischemia reperfusion in rats

目的肢体远隔缺血预处理对缺血再灌注损伤的保护作用的确切机制尚未明确。文中通过观察肢体远隔缺血预处理对大鼠肌皮瓣缺血再灌注时血清中NO和内皮素(endothelin,ET)含量的影响,探讨其可能的保护机制。方法雄性SD大鼠30只,按随机数字表法分为对照组、缺血再灌注组、预处理组共3组,每组10只。各组建立IR模型对照组仅在胸背动脉处穿线不夹闭,缺血组夹闭胸背动脉3 h,预处理组在缺血处理前30 min夹闭右股动脉10 min后恢复血流灌注10 min,进行3个循环。3组大鼠分别在缺血前(T_0)、缺血3 h(T_1)、再灌注1 h(T_2)时于左股静脉取血,测定血清中NO、ET的含量,并计算血清NO与ET的比值,术后5 d取背阔肌采用HE染色光镜下观察肌肉组织的形态学改变。结果与缺血组比较,预处理组在T_1、T_2时间点血清NO含量明显升高[(14.163±2.153)μmol/L vs(16.779±1.979)μmol/L,(10.355±1.913)μmol/L vs(13.127±1.726)μmol/L,P<0.05],血清ET含量明显降低[(240.772±13.734)pg/m L vs(224.662±13.635)pg/m L,(323.160±18.825)pg/m L vs(281.467±16.478)pg/m L,P<0.05],血清NO/ET比值明显增加[(0.059±0.007)vs(0.075±0.006),(0.032±0.004)vs(0.047±0.005),P<0.05],术后5 d肌皮瓣组织病理学损伤减轻。结论肢体远隔缺血预处理所引起的血清NO的水平升高、血清ET的水平降低及血清NO/ET比值升高可能是其对肌皮瓣的缺血再灌注损伤保护的重要机制之一。

Objective Limb remote ischemic preconditioning( LRIP) can protect against ischemia reperfusion-induced injury,but its mechanism is not yet clear. This study was to explore the possible protection mechanism of LRIP by investigating its effect on the levels of serum nitric oxide( NO) and endothelin( ET) following myocutaneous flap ischemia reperfusion( IR) in rats. Methods Thirty male SD rats were equally randomized into a normal control,an IR,and an LRIP group. IR was induced by 3-hour occlusion of the thoracodosal artery followed by 1-hour reperfusion. The rats in the LRIP group underwent 10-minute occlusion of the right femoral artery at 30 minutes before ischemic preconditioning,with the procedure repeated 3 times. Blood samples were collected from the left femoral veins of the 3 groups of rats prior to ischemia( T_0),3 hours after ischemia( T_1),and 1 hour after reperfusion( T_2),respectively,followed by measurement of the levels of serum NO and ET and NO/ET ratio. At 5 days after operation,pathological changes of the latissimus dorsi muscle were detected by HE staining. Results Compared with the IR rats,the LRIP group showed significantly increased levels of serum NO at T_1( [14. 163 ± 2. 153] vs [16. 779 ±1.979]μmol/L,P < 0. 05) and T_2( [10.355± 1.913] vs [13.127±1.726]μmol/L,P < 0. 05),decreased contents of serum ET at T_1( [240.772±13.734]vs [224.662±13.635]pg/m L,P<0.05) and T_2( [323.160±18.825]vs [281.467±16.478]pg/m L,P<0.05),andelevated NO / ET ratios at T_1( 0.059±0.007 vs 0.075±0.006,P<0.05) and T_2( 0.032±0.004 vs 0.047±0.005,P<0.05). At 5 days after operation,the myocutaneous flap injury was significantly improved. Conclusion LRIP increases the level of serum NO,reduces the content of serum ET,and elevates the ratio of serum NO / ET,which may be the mechanisms of its protecting the myocutaneous flap against IR-induced injury.