家兔鞘内注射复方倍他米松的神经毒性

The neurotoxic effect of intrathecal betamethasone compound in rabbits

目的 观察鞘内注射复方倍他米松的神经毒性。方法 选择24只成年家兔，随机分为四组。Ⅰ组：不施加任何处理；Ⅱ组：经枕骨大孔向兔蛛网膜下腔注射生理盐水0.2ml，每周1次；Ⅲ组：除注射药为复方倍他米松200μg(0.2ml)外，其余处理同Ⅱ组；Ⅳ组：注射复方倍他米松400μg(0.2ml)，其余处理同Ⅱ组。3周后处死动物，用生理盐水及戊二醛灌注，取出颈部脊髓(C_(1～6)放入4℃2%戊二醛内做后固定。观察脊髓组织细胞形态的变化。结果 Ⅰ、Ⅱ组脊髓组织细胞形态未见异常；Ⅲ、Ⅳ组脊髓组织细胞的病理改变主要为神经纤维水肿、脱髓鞘、神经元突起消失、结构模糊，线粒体肿胀、空泡变性。结论 鞘内注射复方倍他米松可引起脊髓的损害。

Objective To assess the safety of intrathecal administration of betamethasone.MethodsTwenty-four adult white rabbits of both sexes were randomly divided into four groups with 6 rabbits in each group.Group Ⅰ (blank control group)in which nothing was injected intrathecally;group Ⅱ(NS control group)in whichnormal saline(NS)0.2ml was injected into the subarachnoid space through great occipital foramen once a weekand the animals were killed at the end of the 3rd week;in group Ⅲ and Ⅳ betamethasone 200 μg or 400 μg in 0.2ml was injected intrathecally once a week instead of NS.The animals were anesthetized and killed by intra-aorticinjection of NS and 2% glutaraldehyde.The cervical section of the spinal cord(C_(1-6))was immediately removedand fixed with 2% glutaraldehyde for microscopic examination.Results No neural histo-pathologic changes shownby microscopic examination were observed in group Ⅰ and Ⅱ.In group Ⅲ and Ⅳ microscopic examination showeddifferent degrees of swelling and demyelination of the nerve fibers and edema and vacuolization ofmitochondria.Conclusion Intrathecal betamethasone can damage the spinal cord.