The Change Of NOS In The Brain Tissue Of PD Rabbit Model And The Neuroprotection Role Of NOS Inhibitor L-NNA In PD Model

The animal model of Parkinson's disease was established with rabbits in this paper, and then Madopar and NOS inhibitor L-NNA were respectively used to treat the successful animal model. To study the relationship between the pathologic mechanism of PD and NO, and the effect of NOS inhibitor L-NNA on NO, NOS and dopaminergic neuron in the main diseased region, the content of NO, the activity of NOS and the expression of NOS positive neurons in frontal lobe, Substantia Nigra, Corpus Striatum were determined in every group of rabbits.The method of modeling Parkinson disease (PD) by injecting 6-hydroxydopamine (6-OHDA) into right side of rabbit corpus striatum with cerebral stereotaxis and microinjection technique was used in this study, and then behavior test and Immunohistochemical method were used to detect the PD rabbit model. The result of behavior test showed there were 80% of rabbits achieving the standard of success. TH immunohistochemical staining showed that the TH positive neurons were seen within the nigral in normal control group, sham surgery group, and the unlesioned side of model group. They had the hyperchromic cytoplasm, the clear tubers, numerous positive cells and the long axons, which had no noble change in above three groups. While in the opposite area of the model group TH positive neuron staining became lighter, cell body and tuber got blurrier, especially, the number and the axons` length of the TH-positive neurons decreased and got shorter dramatically than that in the unlesioned side of the model group and the other two groups. The PD rabbit model's reliability was confirmed by the performance test result.The level of NO in the serum, the content of NO, the activity of NOS and the expression of NOS positive neurons in frontal lobe, Substantia Nigra, Corpus Striatum were determined in every group of rabbits by the method of nitric acid reductase and metabolic chemistral method. Results: there was a significant increase of NO levels in the serum and every brain tissue of model group and madopar therapy group compared with control group and sham surgery group, while there was no noble difference between L-NNA therapy group and control groups. The order of TNOS activity in frontal lobe, Substantia Nigra, Corpus Striatum of all groups were: the lesioned side of model group> the lesioned side of madopar therapy group> the unlesioned side of model group> the lesioned side of L-NNA therapy group>normal group and sham surgery group. In addition, the order of activity of iNOS and nNOS in frontal lobe, cNOS in the Corpus Striatum, iNOS in the midbrain (including the Substantia Nigra ) was as the same as the activity of TNOS. Nevertheless, the iNOS activity in Corpus Striatum and nNOS in midbrain (including the Substantia Nigra) were low in every group. Besides, there was no noble difference in all groups.TH-positive neuron in Substantia Nigra and nNOS, iNOS positive neurons in frontal lobe, Substantia Nigra, Corpus Striatum were observed with immunohistochemical staining. Results: there were the contrary trend between the expression of nNOS and iNOS in frontal lobe, iNOS in Substantia Nigra, nNOS in Corpus Striatum and TH-positive neuron in Substantia Nigra. Compared with the madopar therapy group, NOS positive neurons in L-NNA therapy group rabbits were close to the level of control group rabbits. Finally, there was no nNOS positive neurons observed in Substantia Nigra, and no iNOS positive neurons in Corpus Striatum.The results indicated that the missing and death of dopaminergic neurons in the lesioned side of model group rabbits were accompanied by increases of NO content in chief brain tissue and the expression of nNOS and iNOS in frontal lobe, iNOS in Substantia Nigra, nNOS in Corpus Striatum. They suggested NO may be involved in the pathogenesis of PD rabbit model, and there were different isoforms of NOS playing a major role in different brain tissue. Moreover, the protection of NOS inhibitor L-NNA in dopaminergic neurons was good. In view of the similarity between the model and PD patient, NO may be involved in pathogenesis of PD, which provides a new thread of PD Pharmaprojects.