单次剂量注射重组人促红细胞生成素对围生期缺氧导致惊厥新生大鼠的远期影响

摘要

目的 探讨单次剂量注射重组人促红细胞生成素(rhEPO)对围生期缺氧导致惊厥的新生大鼠的远期神经保护作用.方法 生后10 d(即P10)新生大鼠104只,随机分成4组各26只.①缺氧-EPO组:腹腔注射rhEPO(1 000 U/kg),0.5 h后置急性缺氧模型装置(氧浓度低至4%);②缺氧-生理盐水(NS)组:腹腔注射等量生理盐水后置入同上缺氧密闭装置;③常氧-EPO组:相同时间点腹腔注射rhEPO后置常氧浓度的同样密闭装置;④常氧-生理盐水组:相同时间点腹腔注射等量生理盐水后置入同上常氧浓度密闭装置.在P30,Y-型电迷宫测试大鼠的学习记忆能力,戊四氮测试大鼠药物性惊厥的敏感性,尼氏染色评估神经元细胞的丢失情况,Timm 染色观察苔藓纤维发芽情况.结果 围生期缺氧导致惊厥的程度及敏感性在缺氧-EPO组和缺氧-NS两组间比较差异无统计学意义.在P30时间点,缺氧-EPO 组大鼠Y-型电迷宫测试中达到学会标准所需次数明显少于缺氧-NS组(P ＜ 0.05),与常氧组比较差异无统计学意义;24 h记忆保持率明显高于缺氧-NS组(P ＜ 0.05),与常氧组差异无统计学意义;对戊四氮所致惊厥的敏感性较缺氧-NS组明显降低(P ＜ 0.05),较常氧组增高(P ＜ 0.01);各组大鼠均未见明显神经元细胞丢失;缺氧-EPO组大鼠齿状回颗粒细胞上层的苔藓纤维发芽分数和缺氧-NS 组差异无统计学意义,均较常氧组增高(P ＜ 0.05),常氧两组均未见明显苔藓纤维发芽.以上各项测试结果在常氧组间差异均无统计学意义.结论 EPO提高了围生期缺氧导致惊厥的新生鼠在发育期(P30)的学习和记忆能力,降低了对化学致疒间剂的发作敏感性,rhEPO对围生期缺氧导致惊厥的大鼠有远期的神经保护作用.EPO对围生期缺氧惊厥大鼠发展为癫疒间无明显的抑制作用.%Objective To determine if pre-treatment with erythropoietin (EPO) in neonatal rats suffering from hypoxia-induced seizures on postnatal day 10 ( P10) has possible long-term neuroprotective effects on subsequent development on postnatal day 30 (P30).Methods A total of 104 puppy rats on P10 were randomly divided into four groups: hypoxia-EPO group (n = 26) : pre-treated with EPO (1 000 U/kg i.p.) and half an hour later subjected to acute hypoxia (down to 4％ O2); Hypoxia-NS group (re = 26) : intraperitoneally injected with saline and half an hour later subjected an acute hypoxic episode as described above; Normoxia-EPO group (re = 26) : injected with EPO and sham manipulation; Normoxia-NS group (n = 26) : injected with saline and sham manipulation.On P30, Y-maze test was used to estimate the competence of learning and memory, seizure susceptibility was tested by pentylenetetrazol (PTZ) , Nissl staining was performed to analyze cell loss, and Timm staining was performed to evaluate mossy fiber sprouting.Results The degree of seizure and seizure susceptibility in perinatal hypoxia were not obviously different between two hypoxia groups.On P30, hypoxia-EPO-treated rats needed less training frequency to learn the standard than those in hypoxia-NS group (P ＜ 0.05), but there were no significant differences between hypoxia-EPO group with normoxia groups in the Y-maze test.The rate of 24 hour retention of memory in hypoxia-EPO-treated rats was higher than that in hypoxia-NS group rats (P ＜ 0.05) , but no statistical difference was found as compared with other two normoxia groups.The PTZ-induced seizure susceptibility of hypoxia-EPO-treated rats was lower than that in hypoxia-NS treated rats (P ＜ 0.05) , but was higher than that in normoxia groups (P ＜ 0.01).Nissl staining did not show obvious neuron cell loss after hypoxia-induced seizures in all groups.Hypoxia-EPO-treated rats did not display different Timm staining in supragranular zone of the dentate gyrus compared with hypoxia-NS-treated rats, but both of them showed more Timm staining than normoxia groups (P ＜ 0.05).Conclusions The EPO might enhance the competence of learning and memory of the rats (P30) at the development stage who were subjected perinatal hypoxia-induced seizures on P10.EPO could decrease the seizure susceptibility by chemical convulsion induction on P30, which suggests that EPO have the potential long lasting neuroprotective effect on this particular animal model of perinatal hypoxia-induced seizures.Nevertheless, EPO did not show effects to inhibit the possibility of long-term development to epilepsy.