催产素对孕晚期胎鼠神经保护作用的研究

Neural protection of oxytocin on rat fetal hippocampus in late pregnancy

目的研究孕晚期催产素对胎鼠海马的神经保护作用及其机制。方法将孕20天胎鼠全脑制作成厚2～3mm的海马脑片。各组脑片经过药物人工脑脊液灌流后给予缺氧无糖模型15min，苏木素．伊红染色、尼氏染色和原位末端标记法检测评价缺氧损伤程度。结果经过缺氧无糖后，10^-6、10^-7、10^-8mol／L催产素＋γ氨基丁酸组CA1、CA3区尼氏染色神经元密度分别为81．27±4．57、83．33±5．75、79．53±5．03、38．53±6．56、33．60±4．21、32．93±3．65；原位末端标记法凋亡神经元为4．87±1．51、5．47±1．33、6．07±1．28、3．07±1．39、1．80±0．67、2．13±0．74，对照组CA1、CA3区尼氏染色神经元密度为70．17±4．95、29．33±5．96；原位末端标记法凋亡神经元为11．67±3．18、4．78±1．80。10^-6、10^-7、10^-8mol／L催产素＋γ．氨基丁酸组CA1、CA3区尼氏染色神经元密度与对照组CA1、CA3区相比差异有统计学意义（t分剐为-9．407、-8．864、-7．207、-5．427、-3．925、-3．817，均P〈0．01），10^-6、10^-7、10^-8mol／L催产素＋γ-氨基丁酸组CA1、CA3区凋亡神经元数目与对照组CA1、CA3区相比差异有统计学意义（t分别为17．428、18．041、16．931、4．761、17．213、13．859，均P〈0．01）。催产素＋γ-氨基丁酸不同剂量之间差异无统计学意义（P〉0．05）。结论催产素对孕晚期胎鼠海马有神经保护作用，其机制可能与γ-氨基丁酸有关。

Objective To study neuroprotective effect of oxytocin on rat fetal hippocampus in late pregnancy and its mechanisms. Methods The brain tissues of the fetal rats in late pregnancy （20 days after gestation） were taken and brain slices with thickness of 2 ~ 3mm containing hippocampal structures were prepared. After perfusion with artificial cerebral spinal fluid （ACSF） （ in group A, ACST containing no other drugs; in group B, ACSF containing 10^-4mol/L of gamma-amimobutyric acid （GABA） ; in group C, ACSF containing 10^-6 mol/L of OT, 10^-4 mol/L of BIC （ blocker of GABA ）and 10^-4 mol/L of GABA; in group D, ACSF containing respective 10^-6, 10^-7 and 10^-8 mol/L of OT and10^-4 mol/L of GABA ） for 15min, then brain slices containing hippocampal structures in group were kept in the oxygen and glucose deprived （OGD） ACSF for 15 min to establish a hypoxic model. The hematoxylin-eosine staining, Nissl-staining and terminal deoxynuleotide transferase- mediated dUTP nick end labeling （TUNEL） technique were used to evaluate the neural damage. Results After oxygen and glucose deprivation for 15 min, the neural densities in CA1 and CA3 areas of hippocampus in respective 10 ^-6, 10^ -7 and 10 ^-8 mol/L of oxytocin （OT） and GABA groups （ OT ＋ GABA groups ） by Nissl＇ s staining were 81.27 ± 4.57, 83.33 ±5.75, 79.53 ±5.03, 38.53± 6.56, 33.60 ± 4.21 and 32.93±3.65 respectively, while those in the control groups were 70.17± 4.95 and 29.33± 5.96 respectively, there were significant differences in the neural density between different OT ＋ GABA groups and the control group （t = - 9.407, - 8. 864, - 7. 207, - 5. 427, - 3. 925 and - 3. 817 respectively, all P 〈 0.01 ）. The number of apoptostic neurons in CA1 and CA3 areas of hippocampus in respective 10^-6, 10^-7 and10^-8mol/L of OT ＋ GABA groups were 4.87 ± 1.51, 5.47 ± 1.33, 6.07 ±1.28, 3.07 ±1.39, 1.80 ±0.67 and 2.13±0.74 respectively, while those in the control groups were 11.67± 3.18 and 4.78±1.80 respectively, there were significant differences in the number of apeptostic neurons in CA1 and CA3 areas of hippocampus between different OT ＋ GABA groups and the control group （t = 17. 428, 18. 041, 16.931, 4. 761, 17. 213 and 13. 859 respectively,all P 〈 0.01 ）. Between different dosages of OT ＋ GABA groups there were no statistical differences in number of apoptostic neursons （ all P 〉 0.05）. Conclusion Oxytocin has neural protective role for rat fetal hippocampus in late pregnancy, and mechanism of action maybe related to GABA.