早期穴位电针治疗对局灶性脑缺血大鼠脑缺血皮质胰岛素样生长因子-1表达的影响

Effects of electroacupuncture on IGF-1 in the ischemic cortex after cerebral ischemia

目的观察健肢或患肢早期穴位电针治疗对局灶性脑缺血大鼠脑缺血皮质胰岛素样生长因子-1（IGF-1）mRNA和蛋白的时序性变化，探讨穴位电针治疗脑卒中效果的可能相关机制。方法采用线栓法建立局灶性脑缺血模型，将54只建模成功SD大鼠按随机数字表法分为健肢治疗组、患肢治疗组和对照组，每组18只，每组再按实验观察时间随机分为7、14和21d三个时间点亚组，每个时间点6只大鼠。造模成功24h后对治疗组给予浅麻醉行穴位电针治疗，每组各时间点结束24h内分离脑缺血皮质，采用实时荧光定量反转录酶-聚合酶链锁反应（RT—PCR）和蛋白质印迹（Westernblot）法测定IGF-1mRNA表达和蛋白含量。结果①脑缺血后，对照组大鼠脑缺血皮质IGF-1蛋白表达在缺血后第7天、第14天和第21天逐渐下降，各时间点亚组间比较，差异均有统计学意义（P〈0．01）；患肢治疗组蛋白表达趋势与对照组相同，且高于同时间点对照组（P〈0．01）；健肢治疗组在第14天的IGF-1蛋白含量显著高于同时间点患肢治疗组和对照组（P〈0．01），而在第21天时低于同时间点患肢治疗组，但仍高于同时间点对照组（P〈0．01）。②健肢治疗组脑缺血皮质IGF-1mRNA表达在第7天、第14天和第21天逐渐降低，各时间点亚组间差异均有统计学意义（P〈0．01）；且健肢治疗组第7天的基因表达量显著高于同时间点患肢治疗组（P〈0．01），健肢和患肢治疗组分别为同时间点对照组的6．8倍和3．0倍；健肢治疗组在第14天时的基因表达量低于同时间点患肢治疗组（P〈0．01），健肢和患肢治疗组分别为同时间点对照组的3．3倍和5．7倍；健肢治疗组和患肢治疗组的第21天脑缺血皮质的IGF-1mRNA表达均低于同时间点的对照组（P〈0．01）。结论早期穴位电针治疗能增加局灶性脑缺血大鼠缺血脑皮质IGF-1mRNA表达及蛋白含量。健肢穴位电针干预能更早且更大程度地诱发IGF-1mRNA表达增高及蛋白含量增高持续时间较长；脑卒中早期健肢穴位电针干预效果可能优于患肢。

Objective To investigate the effects of electroacupuncture （EA） on affected and healthy limbs and on the regulation of insulin-like growth factor-1 （ IGF-1 ） mRNA and proteins in the cerebral cortex early after fo- cal ischemic. Methods A model of focal cerebral ischemia was established in 54 SD rats using the suture occlusion method. They were then randomly divided into an affected limb therapy group （ ALTG, n = 18） , an unaffected limb therapy group （UALTG, n = 18） , and a control group （CG, n = 18）. Each group had a 7-day subgroup, a 14-day subgroup and a 21-day subgroup with 6 rats in each. Rats in the experimental groups received EA beginning 24h after the occlusion. Rats in each subgroup were sacrificed in a random order on the 7th, 14th and 21st days and the ische- mic cerebral cortexes were quickly dissected. The specimens were frozen in liquid nitrogen before being analysed for IGF-1 mRNA expression by RT-PCR and for IGF-1 protein by Western blotting. Results （~After occlusion, IGF- 1 protein levels in the ischemic cortexes of the CG declined from the 7th through the 21st day. Rats in the ALTG had significantly higher levels compared with the CG at all time points. The UALTG had the highest values on the 14th day, but was lower than the ALTG and higher than the CG at the 21st day. （1）IGF-1 mRNA levels in the ischemic cortexes of the UALTG declined from the 7th through the 21st day. At day 7 the results of the UALTG were 6.8 times higher than the CG, and the ALTG was 3.0 times higher. At day 14 levels in the UALTG were significantly lower than those in the ALTG. At that point the results of the UALTG rats were 3.3 times higher than those of the CG and the ALTG was 5.7 times higher. On day 21 levels in both the UALTG and ALTG were significantly lower than in the CG. Conclusions EA intervention at an early stage of focal cerebral ischemia can improve the expression of IGF-1 mRNA and protein levels in the ischemic cortex. Treating the unaffected limb can evoke more IGF-1 mRNA expres- sion earlier and with relatively longer duration, and generate relatively longer protein increases. EA administered to the unaffected limb was more effective in the early stage of stroke.