脐血单个核细胞对血管性痴呆大鼠脑组织BDNF、NGF的影响

Effects of intracarotid administration of human cord blood mononuclear cells on expressions of brain-derived neurotrophic factor and nerve growth factor in rats with vascular dementia

目的观察颈内动脉输注脐血单个核细胞（HCMNCs）对血管性痴呆（VD）大鼠脑组织脑源性神经营养因子（BDNF）和神经生长因子（NGF）表达及大鼠学习记忆能力的影响。方法改良Pulsinellis四血管阻断法建立VD大鼠模型；大鼠受用随机数字表法分为对照组、模型组和治疗组；每组又分为2，4，8周三个时相点，每时相点12只。体外分离HCMNCs，术后24h颈内动脉输注3×10^6个BrdU标记细胞于治疗组；利用穿梭箱系统和ELISA法检测注射HCMNCs后2，4，8周VD大鼠学习记忆能力以及脑组织BDNF和NGF含量的变化。结果模型组大鼠主动回避反应比率显著低于对照组（P〈0．01），治疗组较模型组显著提高（P〈0．01）。术后2周模型组大鼠脑BDNF、NGF含量较对照组显著增高（P〈0．01），4周时达到高峰（P〈0．01），8周时则明显下降，与2，4周时相比有显著性差异（P〈0．05）；治疗组大鼠脑BDNF、NGF含量较模型组显著升高（P〈0．01），4周时最高（P（0．05，P〈0．01），8周时略有下降，但仍维持在较高水平，与2，4周时相比无统计学意义（P〉0．05）。结论颈内动脉输注HCMNCs可显著改善VD大鼠学习记忆能力，推测原因为通过增加VD大鼠脑组织BDNF和NGF发挥作用。

Objective To explore the effects of intracarotid administration of human cord blood mononuclear cells （HCMNCs） on the expressions of brain-derived neurotrophic factor （BDNF） and nerve growth factor （NGF） and the learning-memory abilities in the vascular dementia （VD） rats. Methods The VD rat model was established by modified Pulsinellis 4-vessel occlusion （4 VO）. The rats were randomly divided into a control group, a model group and a treatment group. The three groups were observed at three time points： 2 w, 4 w and 8 w, twelve rats in each time point. HCMNCs were isolated from human umbilical cord blood in vitro. The treatment group received intracarotid infusion of 3 ×10^6 HCMNCs which were prelabeled with BrdU in vitro. The learning-memory abilities and the contents of BDNF and NGF were observed at 2, 4 and 8 weeks by computerized shuttle-training case and enzyme-linked immunosorbent assay （ELISA）. Results Active avoidance response （AAR） ratio in the model group was significantly decreased compared with the control （P〈0.01）, and the treatment group was significantly higher than the model group （P〈0.01）. The contents of BDNF and NGF in the model group was significantly higher than those in the control, increased to the highest level at 4 weeks, and then decreased at 8 weeks, but compared with that at 2, 4 weeks, significant difference was found （P〈0.05）. Com pared with the model group, the contents of BDNF and NGF in the treatment group were significantly increased after infusion with HCMNCs, increased to the highest level at 4 weeks （P〈0.05, P〈0.01）, and then decreased a little at 8 weeks but maintained the high level that was not significantly different from that at 2, 4 weeks （P〉0.05）. Conclusions Intracarotid administration of HCMNCs significantly improves the leaming-memory abilities, possibly through increasing the contents of BDNF and NGF in the VD rats.