| Objectives (1)To observe the praxiology alternation of 6-hydroxydopamine (6-OHDA) lesioned rats in substantia nigra pars compacta at various time intervals. (2)To observe the microstructural and ulrastractural changes of the dopaminergic neurons in substantia nigra pars compacta. (3)To observe the expression of c-fos in ipsilateral striatum after i.c. injection of the dopaminergic agonist apomorphine hydrochloride. (4)To explore the correlation between behavioral changes, c-fos expression and DA lesion size. Methods 60 Sprague-Dawley rats were randomly divided into normal control group ( 10 rats ), experimental control group ( 10 rats ) and experimental group ( 40 rats, divided into 1d, 7d, 14d, 21d group according to scheduled time intervals ). Experimental rats received a unilateral injection of the neurotoxin 6-OHDA into the substantia nigra pars compacta ( SNc ), which led to dopaminergic denervation differentially, while normal controls no operation and experimental controls vehicle containing saline and 2.0% ascorbic acid. Behavioral changes were observd with the APO induced rotation and the open-field test 1d, 3d, 5d, 14d, 21d after lesion. Dopaminergic degeneration in SN and c-fos expression in the caudate-putamen were investigated with HE and Nissl body staining, eletronicmicroscopic and immunocytochemistry methods. And the results of TH and c-fos was detected by computerized image pattern analysis. All experimental results were statistical analysed by the software of SPSS11.5. The Pearson's correlation coefficient was applied to analyze the correlation between all paramenters ofopen-field test and DA-depletion. Results (1) APO induced rotation: the experimental rats showed an ipsilateral asymmetry in turning behavior and no tendency to recover spontaneously 7d after lesion, circling quantities and velocity and latent period increasing gradually since then. It was up to >7 circles/min on 14d. (2) All paramenters of open-field test. (1) Turning behavior: on day 1, experimental rats showed an ipsilateral asymmetry in turning, differed between this group and all contols (P < 0.05). On day 3 and 5, asymmetry index of experimental groups came back to the level of the controls (P > 0.05), lower than Id, 14d, 21 d (P < 0.05). From then ipsilateral asymmetry index increasd sharply (P < 0.05). (2) Scanning behavior: On day 1, all lesion groups had less scanning (P < 0.01). They showed indications towards recovery 3d and 5d after lesion, and then decreased steadily. There were significant differences between 3d, 5d groups and Id, 7d, 14d, 21 d groups (P < 0.01). (3) Locomotion: Variety tendency of all lesion groups showed a normal distribution. There was no differences between 5d group and the contols (P > 0.05) while significant differences exited between 5d and Id, 14d, 21d groups (P < 0.01). (4) Rearing: There were significant differences between experimental groups and the controls (P < 0.01). Yet on day 3 and 5, there were a tendency to recovery though still lower than the level of the controls, but it yielded significant differences compared with groups 1d and 21d(P < 0.05). (5) Grooming: There were no differences between all groups (P > 0.05). (3) HE and Nissle body staining showed that in the 6-OHDA lesioned SNc the quantitities of dopaminergic neurons decreased notably, glialocytes infiltrated around the needle tract and lesion site from Id to 21d after lesion. There were little differences between two lateral SNc of the controls. (4) The eletronicmicroscopic structure of ipsilateral dopaminergic neurons were severe by degrees, including that rough endoplasmic reticula and Golgi complexes expanded and swelled, mitochondria swelled and ruptured, mitochondrial crista broke, ribosomal granules lessened, and lysosome increased. In striatum myelin sheaths...
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