K_(ATP)开放剂克罗卡林对新生鼠缺氧缺血性脑损伤细胞凋亡的影响

The Effect of the ATP-sensitive Potassium Channel Opener Cromakalim on Cell Apoptosis of Hypoxic-ischemic Brain Damage in Neonatal Rats

目的:探讨ATP敏感性钾通道(KATP)开放剂克罗卡林(cromakalim)对新生大鼠缺氧缺血性脑损伤(hy-poxic-ischemic brain damage,HIBD)细胞凋亡的影响,为临床治疗新生儿缺氧缺血性脑病提供依据。方法:建立新生大鼠HIBD模型,应用HE染色、DNA原位末端标记法(TUNEL)、免疫组化染色方法观察正常对照组、假手术组、HIBD组,克罗卡林用药组(用药1组),克罗卡林+格列苯脲用药组(用药2组)病理变化、细胞凋亡及Bcl-2,Bax蛋白表达情况。结果:①HIBD组大脑皮质区病理变化明显,用药1组病理变化减轻,用药2组病理变化加重;②对照组及假手术组见少量凋亡细胞;HIBD组凋亡细胞明显增多,与对照组及假手术组比较差异有显著性(P<0·01);用药1组凋亡细胞明显减少,与HIBD组比较差异有显著性(P<0·01);用药2组凋亡细胞与HIBD组比较差异无显著性(P>0·05);③正常对照组及假手术组大脑皮质区Bcl-2有一定量的表达,Bax几乎无表达,HI后该区Bcl-2表达减弱,Bax表达增强,用药1组Bcl-2表达较HIBD组明显增强(P<0·01),Bax表达明显减弱(P<0·01),而用药2组Bcl-2表达及Bax表达与HIBD组比较差异无显著性(P>0·05)。结论:HIBD后Bcl-2蛋白表达减弱,Bax蛋白表达增强,细胞凋亡增加;克罗卡林可上调Bcl-2表达,下调Bax表达,使凋亡细胞减少,而KATP阻断剂格列苯脲可拮抗克罗卡林以上作用,这可能是克罗卡林治疗新生儿缺氧缺血性脑损伤的机制之一。

Objective： To investigate the effect and mechanism of KATP opener cromakalim on cell apoptosis of hypoxic, ischemic brain damage in the newborn rats. Methods： After the establishment of hypoxic - ischemic brain damage animal model in the newborn rats, the pathologic changes, neural cell apoptosis, and the expression of Bcl -2 and Bax were observed in control group, pseudo -operation group, cromakalim affected group and cromakalim plus gliberclamide affected group through the techniques of HE staining, TUNEL staining and immunohistochemical staining. Results： The pathological changes of the cortex in HIBD group were apparent than those of the cromakalim affected group. The apoptosis cells increased in HIBD group and decreased in cromakalim affected group. The expression of Bel - 2 were not obvious in control group and pseudo - operation group. There were lower expression of Bel - 2 in the HIBD group, but the expression of Bax increased in the HiBD group. The expression of Bcl -2 in the cromakalim affected group was more obvious than that of HIBD group, but the expression of Bax in the cromakalim affected group was less obvious than that of HIBD group （P 〈0.01 ） . The KATP blocker gliberclamide reduced the effect of cromakalim. Conclusion： The expression of Bcl - 2 protein decreases and Bax protein increases after hypoxic -ischemic brain damage, so the apoptosis cells increase, Cromakalim makes Bcl -2 protein expression increase and decrease the expression of Bax protein. It can reduce the apoptosis cells. This maybe the possible therapy mechanism of cromakalim on the hypoxic - ischemic brain damage.