腺苷、二氮嗪及缺血预处理对缺血再灌注损伤肢体的作用

目的　探讨缺血预处理和腺苷（Ade）、二氮嗪（Dia）药物预处理对肢体缺血再灌注损伤的保护作用。方法　将66只SD大鼠随机分为6组:（1）正常对照组;（2）缺血再灌注（IR）组;（3）预处理10 min组（IP 10）:缺血10min后复流10min,重复3次;（4）预处理5min组（IP5）:缺血5min、复流5min,重复3次;（5）Ade预处理组;（6）Dia预处理组。对照组不作缺血处理,其余各组双后肢持续缺血4h,分别于再灌注2、24h检测胫前肌的单收缩、强直收缩力及血清肌酸磷酸激酶（CPK）含量。结果　（1）5及Ade组在再灌注2h及24h较IR组的胫前肌单收缩力显著增加,而与对照组接近。（2）IP10组在再灌注2h时的保护作用不明显,在24h时有一定的保护作用,但弱于Ade及IP5组。（3）Dia组腔前肌的单收缩及强直收缩力在再灌注2h时较IR组降低,而在24h单收缩力显著升高,各预处理组对胫前肌的强直收缩力没有明显的保护作用。IP5、IP10及Ade组在再灌注2和24h时,而Dia组只在再灌注24h时血清CPK显著低于IR组。结论　缺血预处理和腺苷对肢体的缺血再灌注损伤有保护作用;Dia有延迟保护作用;IP5的作用优于IP10组;腺苷预处理可以取得与缺血预处理相当的效果。

Effect of pretreatment with adenosine, diazoxide or ischemic preconditioning on ischemia-reperfusion injury in the limbs of rats

Objective To study the effect of ischemic preconditioning (PC) and pharmacological preconditioning with adeno-sine or diazoxide on ischemia-reperfusion (IR) injury in the limbs of rats. Methods According to different treatment received before ischemic-reperfusion injury, 66 SD rats were divided into 6 groups including a normal control and a ischemia-reperfusion control group, IP10 group in which the rats received 10-min ischemia followed by 10-min interval for reperfusion for 3 times before IR, IP5 group in which the rats were subjected to 5-min ischemia with 5-min reperfusion intervals for 3 times before IR, adenosine (Ade) pretreatment group and diazoxide (Dia) pretreatment group. Except the normal control group, which consisted of 6 rats, each group contained 12 rats, and IR injury was induced by blocking the blood flow in bilateral limbs for 4 h, followed by reperfusion for 2 or 24 h when twitch and spastic contractility of the tibialis anterior muscle and serum creatine phosphokinase (CPK) were measured. Results In IP5 and Ade pretreatment group, the twitch tension of the tibialis anterior muscle of the rats was significantly enhanced after 2 and 24 h of reperfusion, achieving the level of the normal control. The twitch tension was also enhanced in rats of IP10 group at 24 h, but at 2 h, though with less effectiveness than that in IP5 and Ade group. Dia pretreatment reduced twitch and tetanic contraction forces of the tibialis anterior muscle after 2 h of reperfusion, but obviously improved twitch tension at 24 h. Improvement in the tetanic tension, however, was seen in none of the groups. Serum CPK of IP5, IP10 and Ade groups after 2 and 24 h while Dia at only 24 h of reperfusion was obviously lower than that of IR group. Conclusions Ischemic and Ade preconditioning can protect the limbs of rats from ischemia-reperfusion injury, and Dia has delayed protective effect. IP5 is superior than IP10 and Ade PC can produce similar effect to that of ischemic PC.