地塞米松对苯丙胺致小鼠海马CA3区星形胶质细胞激活及结构损伤的影响

Influence of Dexamethasone on Astrocytes Activation and Injury by Amphetamine in Mouse CA3 of Hippocampus

目的观察地塞米松对苯丙胺致小鼠海马CA3区星形胶质细胞激活及结构损伤的影响。方法清洁级雄性C57BL/6小鼠随机分对照组、生理盐水组、苯丙胺组和地塞米松+苯丙胺组。用行为学方法观察动物行为,用免疫组织化学和电镜方法对小鼠海马结构星形胶质细胞的形态和亚细胞形态进行观察。结果 1.正常组和生理盐水组小鼠未出现行为活动异常。苯丙胺组和地塞米松+苯丙胺组小鼠与正常对照组小鼠相比出现明显异常行为活动。2.苯丙胺组小鼠海马结构内GFAP免疫阳性细胞的形态与对照组相比,突起变长、增粗和分支增多(P<0.05),但细胞的数量无明显增多(P>0.05)。地塞米松+苯丙胺组小鼠海马结构内GFAP免疫阳性细胞的形态与苯丙胺组组相比突起变长、增粗和分支增多(P<0.05),但细胞的数量相比无增多(P>0.05)。3.苯丙胺14d和地塞米松+苯丙胺14d组小鼠海马CA3区超微影像结构示星形胶质细胞增生肥大,线粒体肿胀,髓鞘出现松散分离样变。结论苯丙胺导致小鼠出现神经毒性行为学反应,并导致海马结构星形胶质细胞激活以及细胞和亚细胞结构的损伤;地塞米松没有减轻或抑制苯丙胺致星形胶质细胞的激活和损伤。

Objective To observe influence of dexamethasone on astrocytes activation and injury by amphetamine in mouse CA3 of hippocampus. Methods Male C57BL/6 mice were randomly divided into control group, saline group, amphetamine group and dexamethasone＋ amhpetamine group. The changes of animal behavior were observed by be- havioral method. Immunohistochemistry and electronic microscopic methods were used to study changes of astrocytes in CA3. Results 1. Compared with the normal group, Dexamethasone ~ amphetamine and amphetamine group mouse show significant behavioral anomalies. 2. Compared with the normal group, the processes and branches of GFAP immunopositive cells are longer, larger and more than those in amphetamine group（P〈0.05）. But the hum ber of GFAP immunopositive cells are not increased in CA3 subfield of hippocampus at amphetamine group （P〉 0.05）. In Dexamethasone-^-amphetamine group, distribution of GFAP immunopositive cells are similar as ampheta mine group, but its processes were longer and larger than amphetamine group（P〈0.05）. The number of GFAP im- munopositive cells are not increased in CA3 subfield of hippocampus（P〉0.05）. 3. The 14d amphetamine group and t4d dexamethasonc＋amphetamine group of ultrastructure in hippocampal CA3 region of mouse show that astrocytes become hyperplastic and hypertrophic, mitochondria become swollen, medullary sheath was loose and abrupt. Conclusion Amphetamine induced neurotoxicity behaviour of mouse, and caused activation and damage of astuocytes in mouse hippocampus. However, dexamethasone did not inhibit or reduce activation and damage of astrocytes in- duced by amphetamine.