左旋多巴对弱视猫视皮质区神经细胞的影响

目的观察左旋多巴对剥夺性弱视猫视皮质神经细胞形态和超微结构的影响.方法正常组猫2只,弱视组猫、弱视服药组猫各4只.剥夺性弱视猫模型制作为14周.弱视服药组猫服息宁(左旋多巴/卡比多巴)40mg/kg,每日3次,连服8周.将3组猫处死后,切取双侧视皮质17区组织,在光镜和透射电镜下进行观察.结果光镜下弱视组猫视皮质与正常组猫相比较,均显示神经元体积变小,胞浆突起消失或变短;而弱视服药组猫视皮质神经元与弱视组比较,3/4送检标本的神经细胞形态与正常组的形态基本相同,另1/4标本有轻度改善.电镜下弱视组猫视皮质神经细胞全部显示早期类凋亡的改变,特点为核染色质呈碎粉末状,细胞核变形,胞浆减少,粗面内质网池呈囊性扩张,有髓神经髓鞘板层囊状分离等;弱视服药组猫视皮质中有2/3标本未显示有早期类凋亡,神经细胞的形态接近正常,余1/3标本显示轻度早期类凋亡.结论通过观察服用息宁前后弱视猫视皮质神经细胞的形态学变化,显示左旋多巴具有激活和重塑神经细胞的作用.

The effect of levodopa on the visual cortical cells in amblyopic cats

Objection To observe the effect of levodopa on the morphology and ultrastructure of visual cortical cells in amblyopia cats. Methods Ten cats were divided into three groups, including 2 normal cats , 4 amblyopia cats and 4 amblyopia cats with taking medicine. After visually deprived amblyopia model were developed in 14 weeks, levodopa (carbidopa) 40mg/kg were taken in amblyopia cats with medicine taking, three times per day for 8 weeks. Then the visual cortex of three groups of cats were removed and sectioned and observed by light and transmission electron microscope. Results By light microscope, in amblyopia cats the visual cortical cells showed smaller size and cellular processes extinction or shortening;compared with normal cats, but in three of four amblyopia cats with medicine taking showed the similar morphology to normal cats. By electron microscope, in the amblyopia cats, the visual cortical cells showed the features of early apoptosis in all specimens , including plasma decrease, nucleus malformation, nuclear chromatin breaking, rough endoplasmic reticulum dilatation, myelin sheath separation ,etc. In amblyopia cats with medicine taking, the features of visual cortical neurons in two of three specimens were basically similar to these of normal cats and didn't showed the early apoptosis , but in one of three specimen showed a light damages as early apoptosis. Conclusions Based on the morphological and ultrastructural comparison of before and after taking levodopa in amblyopia cats, the results showed levodopa having the roles to active and remodel nerve cells.