不同剂量促红细胞生成素对大鼠脑缺血再灌注损伤后神经细胞凋亡的影响

目的:探讨促红细胞生成素(Epo)对局灶性脑缺血再灌注损伤大鼠神经细胞凋亡的影响.方法:32只雄性SD大鼠随机分成Epo低、中、高剂量组和缺血再灌注组,4组大鼠均采用线栓法阻断一侧大脑中动脉血流2 h再灌注24 h制成局灶性脑缺血再灌注损伤模型.缺血开始时Epo低、中、高剂量组分别腹腔注射Epo 1000 U/kg、3000U/kg、5000U/kg,缺血再灌注组注射等量生理盐水.再灌注24 h后断头取脑,制作石蜡切片,免疫组化染色检测Bcl-2和Bax的表达,TUNEL法检测细胞凋亡.结果:与缺血再灌注组比较,Epo各剂量组凋亡细胞均少,Bcl-2表达较高,Bax表达较少,Bcl-2/Bax比值变大.Epo各剂量组间Bax的表达差异无统计学意义;高剂量Epo组对Bcl-2表达和Bcl-2/Bax比值影响最大;中剂量Epo对细胞凋亡的影响最为显著;低剂量Epo对Bcl-2表达和细胞凋亡的影响最小,对Bcl-2/Bax比值的影响与中剂量相同.结论:不同剂量的Epo对大鼠脑缺血再灌注损伤后皮层神经细胞凋亡的影响不完全相同,3000 U/kg可能最接近最佳应用剂量.

Effects of different doses of erythropoietin on apoptosis of neural cells in rats after ischemia-reperfusion injury

Aim: To explore the effects of different doses of erythropoietin on apoptosis of neural cells in rats after ischemia-reperfusion injury. Methods: A total of 32 male SD rats were randomized into low-dose erythropoietin group, mid-dose erythropoietin group, high-dose erythropoietin group and ischemia reperfusion group. The model of focal cerebral ischemia-reperfusion injury was established by occluding middle cerebral artery(MCA) for 2 h and reperfusing for 24 h. erythropoietin groups received rHu-erythropoietin at 1 000 U/kg , 3 000 U/kg, 5 000 U/kg body weight respectively at very onset of ischemia, while ischemia group received the same dose of normal saline. The brains were removed 24 h after reperfusion. Apoptosis and the expression of Bcl-2 and Bax were observed using TUNEL assay and immunohistology,respectively. Results: Less apoptotic neurons and Bax positive cell, more Bcl-2 positive cell and higher ratio of Bcl-2 to Bax were observed in erythropoietin groups compared with those in ischemia group. Different doses of erythropoietin had the same effects on the expression of Bax; In 5 000 U/kg erythropoietin group, Bcl-2 expression and the ratio of Bcl-2 to Bax changed significantly, and 3 000 U/kg erythropoietin decreased neural cell apoptosis significantly, while 1 000 U/kg of erythropoietin showed less effects on them. Conclusion:Different doses of erythropoietin administration can produce different effects.erythropoietin at a dose of 3 000 U/kg may be the optimal dose.