| Objective: Parkinson's disease (PD) is a common neurodegenerative disorder in middle and aged groups. It is mainly characterized by the progressive degeneration and necrosis of dopaminergic neurons in the substantia nigra of the mesencephalon, which contribute to the deficiency of dopamine in the striatum. With the development of people's aging in the world, it's morbidity has become higher and higher. Despite intensive research into the cause of idiopathic PD, its etiology remains unknown. It's necessary to point out that researchers have always been explored the the cause and pathogenesis of PD from the angle of dopaminergic neurons. While there are also propagation and activation of gliacytes in the subsantia nigra and around the Lewy bodies whether in PD patient or in MPTP-induced mice models of PD. Which had been thought as only a results of dopaminergic neurons'death. Now people have found it nearly impossible to solve the intractable problem only from the angle of dopaminergic neurons.Increasing evidence has suggested a role for gliacytes in the pathogenesis of PD. Gliacytes have the absolute advantage in quantity in brain, which have complicated and close interactions with neurons. For this reason certain alterations of gliacytes' function may change the destiny of the dopaminergic neurons. In addition, the increased quantity of microgliocytes can be observed in normal people or rat PD models along with the increase of the age, and their ability to secrete some pro-inflammatory factors is also enhanced. Since PD is common in the crowd of advanced age, It's natural to postulate that there may exist some relations between the microgliocytes and the degeneration of dopaminergic neurons. The data from the epidemiology shows, having the history of brain hurts, in-utero bacterial or endotoxin exposure in early years and the mobidity of PD are positive related. These data hinted that the activation of microglia cells can take part in the pathogenesis as a kind of background factor. For this reason people started noticing the increase and activation of gliacytes, which are importmant but usually be neglected, and put forward that the gliacytes may participate the degeneration and death of dopaminergic neurons in PD. Since 6-hydroxydopamine(6-OHDA)-induced hemiparkinsonian rats is also a classic model of PD , and whether gliacytes participates the death of dopaminergic neurons in this kind PD model has not yet been reported. In this experiment 6-OHDA was stereotacticly injected into the right striatum of the rats at two sites to fabricate rats PD model. We observed the loss of dopminergic neurons, counted the alternations in quantity of microglia and astrocyte and observed the expression of tumor necrosis factor-alpha(TNF- α) to explore the role of gliacytes in the pathogenesis of PD.Methods: 48 adult male Wistar rats weighted 220±10g were randomly divided into three groups: animal model group(26 rats), sham-operation group (6 rats)and normalcontrol group(6 rats). The 6-OHDA was stereotaxically injected into the right striatum of rats at two sites. Each site received an injection of 10μg/5μl 6-OHDA. The sham group received the same amount of 0.9% saline, rather than 6-OHDA. We used microscope to observe the pathological changes of substantia nigra compacta and striatum in each groups. Observe the loss of DA neurons,account the alteration in quantity of microglias and astrocytes by nigral hematoxylin & eosin (HE) stain and observed the expression of TNF-αin the substantia nigra pars compacta and striatum by immunohistochemical stain under optical microscope. Statistical analysis: Intra-group comparisons, comparisons between groups were done using student's t- test. The P value less than 0.05 was regarded as statistically significant.Results:The substantia nigral HE stain and immunohistochemical stain of TH showed that the dopaminergic neurons in the right substantia nigra pars compacta of the PD model rats vanished markedly, cells were rare and the survivals were atrophic. The... |
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