人脐带血单核细胞移植对缺氧缺血性脑损伤新生大鼠学习记忆功能的影响

Effect of human cord blood mononuclear cells transplantation on the ability of learning and memory of new-born rats with hypoxic - ischemic brain damage

目的探讨人脐带血单核细胞（HCMNCs）移植对新生大鼠缺氧缺血性脑损伤（HIBD）后学习记忆功能的影响。方法新生713龄sD大鼠60只，随机数字表法分为3组，采用Rice法建立HIBD动物模型，缺氧缺血后24h，HIBD＋移植组大鼠腹腔内注入1×107HCMNCs；HIBD＋9g／L盐水组腹腔内注入等量的9g／L盐水；另设空白对照组。出生10d及67d行头颅磁共振成像（MRI）检查，出生35d利用Morris水迷宫实验评估大鼠空间学习记忆能力，后断头取脑，进行鼠脑大体形态学评分，并使用透射电镜观察各组鼠脑损伤部位神经元突触超微结构的改变，进行相关性分析。结果HIBD4-9g／L盐水组与HIBD＋移植组、空白对照组比较，Morris水迷宫实验中第2天开始逃避潜伏期延长[第2天：（61．17±6．22）s比（53．09±7．41）S比（53．53±5．28）s，第3天：（57．26±14．98）S比（49．764±9．40）S比（47．11±7．36）s，第4天：（52．10±6．17）S比（44．164±5．74）s比（41．96±8．97）s]，穿台次数减少[（2．12±1．05）次比（3．06±1．16）次比（3．70±1．17）次]，总运动路程减少[（16．68±3．76）cm比（22．00±3．32）cm比（23．80±2．25）cm]，平均速度减少[（0．284±0．06）em／s比（0．37±0．06）cm／s比（0．404±0．04）cm／s]，在原平台所在象限的运动时间减少[（22．754±4．85）s比（27．884±3．81）s比（28．02±4．09）s]，差异均有统计学意义（P均〈0．05）；脑组织形态学评分增加[（2．82±1．02）分比（1．61±0．92）分比（0．00±0．00）分]；透射电镜观察突触间隙增宽[（26．49±2．42）am比（23．20±2．05）nm比（21．64±4．68）am]，差异均有统计学意义（P均〈0．05）；生后67d头颅MRI检查示残存脑容量减少[（55．29±11．48）％比（75．34±7．02）％比（1004±0．00）％]，差异均有统计学意义（P均〈0．05）。而HIBD＋移植组与空白对照组比较，上述各项指标间差异均无统计学意义（P均〉0．05）；在第4天的Morris水迷宫实验中，各组大鼠的逃避潜伏期与透射电镜观察突触间隙宽度呈正相关（r=0．788，P〈0．05）。结论HCMNCs腹腔内移植可促进新生大鼠HIBD后损伤脑细胞的恢复及学习记忆功能的改善。

Objective To explore the effect of human cord blood mononuclear cells （HCMNCs） transplanta- tion on the ability of learning and memory of neonatal rats with hypoxic -ischemic brain damage（HIBD） and its corre- lation. Methods Sixty 7 - day - old neonatal SD rats were divided into 3 groups randomly. A modified newborn rat model that had a combined hypoxic and ischemic brain damage as described by Rice was used. After 24 h, in the HIBD ＋ HCMNCs group intraperitoneal injection with 1× 107 HCMNCs was given;HIBD ＋ 9 g/L saline group received intrape- ritoneal injection with the equal 9 g/L saline, and a control group was also established. The brain MRI was done to eva- luate the recovery from brain damage 10 d and 67 d after birth. The Morris water maze was used to evaluate the ability of learning and memory 35 d after birth. Then they were beheaded for the brain samples, and morphological grading roughly to mouse, transmission electron microscope were used to evaluate the neurons synaptic ultrastructure changes in each mouse brains injury. At last, correlation analysis was made among groups. Results Compared with HIBD ＋ HCMNCs group and blank control group,in Morris water maze, from the second day, the HIBD ＋ 9 g/L saline showed longer escape latency from the 2 day[ the second day：（61.17 ± 6.22） s vs （53.09 ± 7.41 ） s vs （53.53 ± 5.28） s, the third day：（57.26±14.98） svs （49.76±9.40） svs （47.11 ±7.36） s,the fourth day：（52.10±6.17） svs （44.16 ± 5.74） s, （41.96 ± 8.97 ） s ] , the times through the platform reduced [ （ 2. 12 ± 1.05 ） times vs （ 3.06 ± 1.16） times vs （3.70 ± 1.17） times] ,the total movement distance was reduced [ （ 16.68 ± 3.76） nm vs （22.00 ± 3.32 ） nm vs （ 23.80 ± 2.25 ） nm ], the average speed was reduced [ （0.28 ± 0.06 ） cm/s vs （0.37 ± 0.06） cm/s vs （0.40 ± 0.04） cm/s ], the movement time was reduced [ （ 22.75 ± 4.85 ） s vs （ 27.88 ± 3.81 ） s, （28.02 ± 4.09） s ]（ all P 〈 0.05 ）. The score of the gross morphologic appearance was raised [ （ 2.82 ±1.02） scores vs （ 1.61 ± 0.92 ） scores vs （0. 00 ± 0. 00 ） score ]. Transmission electron microscope showed that the synaptic cleft was widened [ （26.49 ± 2.42） nm vs （23.20 ±2.05 ） nm vs （21.64 ±4.68） nm ] （ all P 〈 0.05 ）. The residual brain volume de- creased 67 d after birth, [ （55.29 ± 11.48 ） % vs （ 75.34 ± 7.02 ） %, （ 100± 0.00） % ], There were no differences be- tween HIBD ± HCMNCs group and the blank control group（ all P 〉 0.05 ）. On the the fourth day in Morris water maze, high correlation existed between the escape latency and the synaptic cleft（ r = 0. 788, P 〈 0.05 ）. Conclusion HCMNCs intraperitoneal transplantation significantly promoted the recovery of injured brain and the ability of learning and memory.