Experimental Study On Varied Expression Of TH In Rat Models Of Parkinson’s Disease

Parkinson’s disease is a kind of common ehronic of neurodegenerative disease which usually occurs among the elderly. The major neurochemical manifestation of this disease is the loss of the neurotransmitter dopamine and its metabolites3,4-dihydroxyphenylacetieaeid in the striatm as a result of the progressive degeneration of the dopaminergic neurons in the substantia nigra. At present, the most common animal model for constructing the Parkinson’s disease is rat, but due to the low success rate and the poor stability of Parkinson’s disease model, it’s hard for us to search for the deep pathogenesis of it and further diagnose and treat it. The tyrosine hydroxylase which is the dopaminergic neuron proteins in the nervous system is the limit enzyme of dopamine synthesis. In this study, the rats of different weights and strains are chosen to establish Parkinson’s disease models. According to the behavioral manifestation of animals and the expression changes of specificity tyrosine hydroxylase, it’s easy to analyse the success rate and choose the models of high success rate and good stability to diagnose and treat the Parkinson’s disease. At the same time, this experiment adopts the method of fluorescence quantitative PCR to determine TH expression changes in rats to study the relationship between TH gene and Parkinson’s disease. This research provides certain theoretical basis and guidance for the diagnosis and treatment of the Parkinson’s disease.Part ⅠThe optimization of establishing the rat models in Parkinson’s DiseaseDifferent weights and strains (SD/Wistar) of rats were chosen to establish the models of Parkinson’s disease. The unilateral stereotaxic intra-striatal double point injection and single point injection of6-hydroxydopamine were adopted to establish Parkinson’s disease of rats. The rats were induced to rotate by injected apomorphine in two weeks after operation. We could compare the success rate of the models which were established by different methods in Parkinson’s disease. We could assess these models by HE staining in morphological observation and also test the expression of TH in damaged side of models in Parkinson’s disease by immune-histochemical staining. According to the behavioral manifestation of animals and the expression changes of specificity tyrosine hydroxylase, it was easy to analyse the success rate and choose the models of high success rate and good stability to diagnose and treat the Parkinson’s disease.Two weeks after operation, the rats continued to rotate to the healthy side. After statistical analysis, the success rate of the single point was significantly higher than the double point injection; the success rate of the weight from180-240g of rats was higher than the weight above250g; while there was no significant difference in different strains. The stability of different weights and different points had significant difference, but the the stability of different strains of rats (SD/Wistar) had no significant difference. The result of HE staining showed that the damaged side of brain in PD rats lacked of neural cells. The result of immunohistochemical staining showed that the number of TH positive cells decreased significantly in the damaged side of brain in PD rats.We can establish higher and more stable models of Parkinson’s disease by using the method of single point of6-OHDA and the rats which has the weight from180g to240g.Part ⅡExperimental study on varied expression of TH in rat models of Parkinson’s DiseaseThis experiment adopts the method of fluorescence quantitative PCR to determine TH expression changes in rats to study the relationship between TH gene and Parkinson’s disease. By studying the changes of the expression level of TH mRNA in the brains of PD rats and the results of immune-histochemical staining in the first part of the experiment, we could analyze the relationship between TH and Parkinson’s disease.There was no significant difference between the damaged and normal brains of the normal rats. Three weeks after operation, the expression quantity of TH in the damaged brain of PD rats was only57.4percent of the normal one. Six weeks after operation, the expression quantity of TH in the damaged brain was31.7percent of the normal one. Eight weeks after operation, the expression quantity of TH in the damaged brain was39.9percent of the normal one. The results of immunohistochemical of TH showed that the positive cells of TH were significantly reduced in the damaged side of the brain.This experiment shows that there is a relationship between the reduction of TH and the Parkinson’s disease. Therefore the pathogenesis of Parkinson’s disease is associated with the reduction of tyrosine hydroxylase. This research provides a certain molecular method to diagnose the Parkinson’s disease, and also provides certain theoretical basis and guidance for the diagnosis and treatment of the Parkinson’s disease.