Panax notoginseng saponins influence on transplantation of neural stem cell-derived dopaminergic neurons in a rat model of Parkinson’s disease

摘要

BACKGROUND: Dopaminergic neurons differentiated from neural stem cells have been successfully used in the treatment of rat models of Parkinson’s disease; however, the survival rate of transplanted cells has been low. Most cells die by apoptosis as a result of overloaded intracellular calcium and the formation of oxygen free radicals. OBJECTIVE: To observe whether survival of transplanted cells, transplantation efficacy, and dopaminergic differentiation from neural stem cells is altered by Panax notoginseng saponins (PNS) in a rat model of Parkinson’s disease. DESIGN, TIME AND SETTING: Cellular and molecular biology experiments with randomized group design. The experiment was performed at the Animal Experimental Center, First Hospital of Sun Yat-sen Uni- versity from April to October 2007. MATERIALS: Thirty-two adult, healthy, male Sprague Dawley rats, and four healthy Sprague Dawley rat embryos at gestational days 14-15 were selected. The right ventral mesencephalon was injected with 6-hydroxydopamine to establish a model of Parkinson’s disease. 6-hydroxydopamine and apomorphine were purchased from Sigma, USA. METHODS: Neural stem cells derived from the mesencephalon of embryonic rats were cultivated and passaged in serum-free culture medium. Lesioned animals were randomly divided into four groups (n = 8): dopaminergic neuron, dopaminergic neuron + PNS, PNS, and control. The dopaminergic neuron group was injected with 3 μL cell suspension containing dopaminergic neurons differentiated from neural stem cells. The dopaminergic neurons + PNS group received 3 μL dopaminergic cell suspension combined with PNS (250 mg/L). The PNS group received 3 μL PNS (250 mg/L), and the control group received 3 μL DMEM/F12 culture medium. MAIN OUTCOME MEASURES: The rats were transcardially perfused with 4% paraformaldehyde at 60 days post-grafting for immunohistochemistry. The rats were intraperitoneally injected with apomorphine (0.5 mg/kg) to induce rotational behavior. RESULTS: Cell counts of tyrosine hydroxylase-positive neurons in the dopaminergic neuron + PNS group were (732±82.6) cells/400-fold field. This was significantly greater than the dopaminergic neuron group [(326 ± 34.8) cells/400-fold field, P < 0.01]. Compared to the control group, the rotational asymmetry of rats that received dopaminergic neuron transplants was significantly decreased, beginning at 20 days after opera- tion (P < 0.01). Rotational asymmetry was further reduced between 10-60 days post-surgery in the dopaminergic neuron + PNS group, compared to the dopaminergic neuron group (P < 0.01). CONCLUSION: Panax notoginseng saponins can increase survival and effectiveness of dopaminergic neurons differentiated from neural stem cells for transplantation in a rat model of Parkinson’s disease.