左旋多巴对单眼形觉剥夺性弱视大鼠视皮质神经细胞形态的影响

发布时间：2018-04-23 18:07

本文选题：左旋多巴 + 形觉剥夺性弱视　；参考：《中南大学》2011年硕士论文

【摘要】：目的：观察不同剂量左旋多巴(Levopoda,LD)对单眼形觉剥夺性弱视大鼠视皮质神经细胞形态的影响,探讨其治疗弱视的可能机制。方法：36只14日龄SD大鼠(中南大学动物部提供),随机分为3组,即弱视对照组、小剂量组、大剂量组,每组12只。缝合右眼眼睑4周后,剪开缝合的眼睑行闪光视觉诱发电位(F-VEP)检查,确定形觉剥夺性弱视模型建立成功后,小剂量组、大剂量组分别以浓度为20 mg/kg、80 mg/kg左旋多巴溶液灌胃,弱视对照组以生理盐水灌胃,每日1次,持续4周后处死大鼠取大脑视皮质行苏木素-伊红染色(HE染色),光镜下观察HE染色视皮质V1区神经细胞的形态,TUNEL法定量检测各组大鼠视皮质神经细胞的凋亡情况。结果：1. F-VEP的P2波潜伏期的变化：给药前各组大鼠剥夺眼F-VEP的P2波潜伏期较未剥夺眼明显延长(P0.05),差异有统计学意义,N2P2波、P2N3波振幅比较,差异无统计学意义(P0.05),未剥夺眼、剥夺眼P2波潜伏期及N2P2波、P2N3波振幅组间比较差异均无统计学意义(P0.05) 2.光镜下HE染色观察视皮质V1区神经细胞形态变化：各组大鼠未剥夺眼相应侧视皮质V1区神经细胞数量及形态均正常；弱视对照组剥夺眼与未剥夺眼比较,神经细胞数量明显减少、体积变小、胞浆减少、胞浆突起变短或消失,胞核变小、变暗,并可见溶解、固缩、碎裂等现象,呈现类凋亡现象；小剂量组剥夺眼与未剥夺眼比较神经细胞数量及形态仅有轻度改变。大剂量组剥夺眼与未剥夺眼比较无明显改变. 3.TUNEL法检测视皮质V1区神经细胞的凋亡及计数:各组大鼠未剥夺眼相应侧视皮质V1区内仅发现少量染色呈绿色荧光的阳性神经细胞,弱视对照组剥夺眼较未剥夺眼相应侧视皮质V1区阳性神经细胞数量明显增多,差异有统计学意义(P0.05),小剂量组剥夺眼较弱视对照组剥夺眼相应侧视皮质V1区阳性神经细胞数量减少,差异有统计学意义(P0.05),大剂量组剥夺眼较小剂量组剥夺眼相应侧视皮质V1区阳性神经细胞数量减少,差异有统计学意义(P0.05)。结论：1.大鼠形觉剥夺性弱视眼F-VEP的P2波潜伏期延长,弱视眼相应侧视皮质V1区神经细胞数量减少,体积变小,呈类凋亡现象。 2.补充外源性左旋多巴能改善大鼠形觉剥夺性弱视眼相应侧视皮质V1区神经细胞的类凋亡现象。 3.左旋多巴减轻弱视所致的视觉中枢神经细胞形态及数量的变化可能是通过抑制视皮质神经细胞的类凋亡,从而参与视觉系统的发育和重塑过程。
[Abstract]:Aim: to observe the effect of Levopododa on the morphology of neurons in the visual cortex of monocular deprivation amblyopia rats, and to explore the possible mechanism of the treatment of amblyopia. Methods Thirty six 14-day-old Sprague-Dawley rats were randomly divided into three groups: amblyopia control group, low-dose group, high-dose group, each group (12 rats). After the right eyelid was sutured for 4 weeks, the eyelids were cut and sutured by flash visual evoked potential (F-VEP) examination. After the establishment of the model of form deprivation amblyopia, the low-dose group and high-dose group were perfused with 20 mg / kg ~ 80 mg/kg levodopa solution, respectively. Amblyopia control group was given normal saline once a day. After 4 weeks, the rats were sacrificed for hematoxylin eosin staining and HE staining. The morphological changes of neurons in the V1 region of the visual cortex were observed by HE staining under light microscope. The apoptosis of the neurons in the visual cortex of each group was detected quantitatively by Tunel method. The result is 1: 1. Changes of latency of P2 wave in F-VEP: the latency of P 2 wave in deprived eyes of rats in each group was significantly longer than that in eyes without deprivation before administration. The difference was statistically significant (P 0 05), and there was no significant difference in amplitude of P 2 P 2 wave P 2 N 3 wave. There was no significant difference in latency of P2 wave and amplitude of P2N3 wave of N2P2 wave in deprived eyes (P 0.05). 2. The morphological changes of neurons in the V1 region of the visual cortex were observed by HE staining under light microscope: the number and morphology of the neurons in the V1 region of the corresponding lateral visual cortex were normal in the undeprived eyes of each group, and those in the amblyopic control group were compared with those in the control group. The number, volume and cytoplasm of nerve cells decreased obviously, the cytoplasmic processes became shorter or disappeared, the nuclei became smaller and darkened, and the phenomena of dissolution, pyknosis, fragmentation and so on were observed, showing the phenomenon of apoptosis-like. There were only slight changes in the number and morphology of nerve cells between the deprived eyes and the undeprived eyes in the low dose group. There was no significant difference between the deprived eyes and the undeprived eyes in the high dose group. 3.TUNEL method was used to detect the apoptosis and counting of neurons in the V1 region of the visual cortex: only a few positive neurons stained green fluorescence were found in the V1 region of the visual cortex without deprivation. In amblyopia control group, the number of positive neurons in V1 region of the corresponding lateral visual cortex was significantly higher in deprived eyes than in non-deprived eyes. The difference was statistically significant (P 0.05). The number of positive neurons in the V1 region of the lateral visual cortex in the low dose group was lower than that in the amblyopic control group. The difference was statistically significant (P 0.05). The number of positive neurons in the V 1 region of the lateral visual cortex in the high dose group was lower than that in the small dose group, and the difference was statistically significant (P 0.05). Conclusion 1. The latency of P2 wave in F-VEP of amblyopia eyes of form deprivation was prolonged, the number of neurons in V1 region of lateral visual cortex of amblyopia eyes was decreased, the volume of neurons decreased, and the amblyopia eyes showed apoptosis-like phenomenon. 2. Supplementation of exogenous levodopa can improve the apoptosis of neurons in the V _ 1 region of the corresponding lateral visual cortex in the form-deprived amblyopia of rats. 3. Levodopa may be involved in the development and remodeling of the visual system by inhibiting apoptosis of the neurons in the visual cortex in order to alleviate the changes in the morphology and number of visual central nervous cells induced by amblyopia.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R777.44

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