脑源性神经营养因子预先给药对大鼠局灶性脑缺血再灌注后神经细胞凋亡的影响

目的探讨不同剂量的脑源性神经营养因子（BDNF）预先给药对大鼠局灶性脑缺血再灌注（I/R）后神经细胞凋亡的影响。方法用大鼠大脑中动脉线栓法（MCAO）建立局灶性脑缺血再灌注模型,BDNF采用侧脑室注射法给药。将30只雄性Wistar大鼠,随机分为5组：正常对照组（C组）、缺血再灌注组（I/R组）、BDNF预先给药低剂量组（L组）、中剂量组（M）、高剂量组（H）;除C组外,其余各组分别行脑缺血1 h再灌注72 h后处死取脑皮层标本待检。采用TUNEL法观察大鼠脑缺血再灌注后脑皮层神经细胞凋亡的变化。结果与I/R组比较,BDNF预先给药各组神经细胞凋亡指数均明显减少（P〈0.01）;在BDNF预先给药各组中,以预先给药高剂量组的神经细胞凋亡指数最小（P〈0.01）。结论不同剂量的BDNF预先给药均能明显减轻脑I/R后神经细胞凋亡,具有不同程度的脑保护作用。且随BDNF预先给药剂量的增加细胞凋亡数量进一步减少。

Effects of BDNF pretreatment on apoptosis following focal cerebral ischemia and reperfusion in rats

Objective:To study the effects of different doses of brain-derived neurotrophic factor(BDNF) pretreatment on apoptosis following focal cerebral ischemia and reperfu-sion in rats.Methods:The model of middle cerebral artery occlusion(MACO) and reperfusion was set up.BDNF was injected into the lateral ventricle.Neuron apoptosis was identified by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling(TUNEL).Thirty Wistar male rats were randomly divided into five groups,with six animals in each:sham operation group(group C),ischemia-reperfusion group(I/R),BDNF pretreatment groups:L,M and H group.Except group C,the other group animals were sacrificed at the timepoint of cerebral ischemia 1h and reperfusion 72h and then the brain cortex was takenfor detecting.Results:Compared with I/R group,the index of neuron apoptosis in BDNF pretreatment groups were decreased significantly(P<0.01).In all of the BDNF pretreatment groups,the neuron apoptosis index in brain cortex were lowest in group H(P<0.01).Conclusion:Different doses of BDNF pretreatment can significantly decrease the number of apoptotic neuronal cells in cerebral cortex,has certain protection against focal cerebral ischemia-reperfusion injury.The number of neuron apoptosis decreases with the increase of the dose of BDNF pretreatment.