The Effect And Mechanism Of Over-expression NQO1 On L-DOPA Induced Dyskinesia

ABM:To study the effect of overexpression NQO1 on Levodopa induced dyskinesia and to further understand the molecular mechanism and strategies in treatment of dyskinesia.METHORDS:The NQO1 transgenic mice were bred and the genotype of filial generation were identified by PCR. Immunohistochemistry was used to compare the expression of NQO1 in brain tissue between NOQ1 transgenic mice and wild type mice. Mice were received unilateral injection of 6-OHDA in the striatum to build Parkinsonism model with the stereotaxic apparatus. Amphetamine-induced rotation test and cylinder test were measured to examine the behavior of lesion mice. The differences in dopamine neurons morphology in the substantia nigra between lesion mice and sham mice were detected by immunohistochemistry. Select the Parkinsonism mice with relatively similar level of symptoms to prepare an animal model of dyskinesia by intraperitoneal injection of L-DOPA and Benserazide Hydrochloride. The cylinder test was used again to measure the therapy effect of mice after L-DOPA treatment. The AIM test was used to compare the severity of dyskinesia between NQO1 transgenic mice and wild type mice. The DA neuron and 5-HT neuron were detected by immunohistochemistry.RESULTS:98 mice were obtained for the subsequent experiment. The NQO1 transgenic mice have significant higher expression of NQO1 than wild type mice. The number of rotations induced by amphetamine in the lesion group was higher than that in the sham operated group. The 6-OHDA lesion group which was compared with sham operated group showed a significant deficit in the use of forelimb contralateral to the lesion side in the cylinder test. The dopamine neuron injury in the substantia nigra of 6-OHDA lesion group was significant. The results from behavior and histology showed that we had successfully built Parkinsonism model in mice with unilateral 6-OHDA lesion in the substantia nigra. The use of left forelimb of drug group increased after administration of Levodopa for 21 days, which showed the therapy effect of L-DOPA treatment. A significant difference of AIM scores between saline group and L-DOPA group in response to long-term L-DOPA treatment was observed. The AIM scores of Tg68 transgenic mice whose expression of NQO1 was higher had a decreasing trend, but no statistical difference. The AIM scores of Tg27 transgenic mice which had a highest expression of NQO1 was lower than that of wild type mice. The number of dopamine neurons in the lesion side of Tg27 NQO1 transgenic mice was greater than that of wild type mice. There was no difference of 5-HT neurons in the periaqeductal gray matter among the mice in each group.CONCLUSIONS:We successfully established Parkinsonism model in mice by unilateral injection of 6-OHDA in the striatum. Compared with wild type mice, dyskinesia was attenuated in Tg27 NQO1 transgenic mice with more TH-positive neurons on the lesion side, suggesting that the mice of overexpression NQO1 mice show an anti-dyskinesia effect. The results did not show any correlation between the 5-HT neurons and dyskinesia.