Achyranthes bidentata polypeptide protects dopaminergic neurons from apoptosis induced by rotenone and 6-hydroxydopamine

It has been well documented that Achyranthes bidentata polypeptides(ABPPs) are potent neuroprotective agents in several types of neurons. However, whether ABPPs protect dopaminergic neurons from apoptosis induced by neurotoxins is still unknown. This study was designed to observe the effect of ABPPk, a purified fraction of ABPPs, on apoptosis of dopaminergic neurons. SH-5YHY cells and primary dopaminergic neurons were pre-treated with ABPPk(25, 50, or 100 ng/mL) for 12 hours. Cells were then exposed to 6-hydroxydopamine(50 or 150 μM) or rotenone(50 or 200 μM) for 36 hours to induce cell apoptosis. Our results demonstrate that ABPPk markedly increased viability in SH-SY5Y cells and primary dopaminergic neurons, decreased lactate dehydrogenase activity and number of apoptotic dopaminergic neurons, elevated mitochondrial membrane potential, and increased Bcl-2/Bax ratio. These findings suggest that ABPPk protects dopaminergic neurons from apoptosis, and that ABPPk treatment might be an effective intervention for treating dopaminergic neuronal loss associated with disorders such as Parkinson's disease.     

Gastrodin inhibits neuroinflammation in rotenone-induced Parkinson's disease model rats

The present study showed that the latency of rats moving on a vertical grid was significantly prolonged,and the number of rats sliding down from the declined plane was increased remarkably,in rotenone-induced Parkinson’s disease model rats compared with control rats.The moving latency recovered to normal levels,but the number of slides was significantly increased at 28 days after model establishment.The slope test is a meaningful approach to evaluate the symptoms of Parkinson’s disease model rats treated with rotenone.In addition,loss of substantia nigral dopaminergic neurons in model rats was observed at 1 day after the model was established,and continued gradually at 14 and 28 days.The expression of tyrosine hydroxylase-positive cells was significantly increased in gastrodin-treated rats at 14 days.Significant numbers of activated microglia cells were observed in model rats at 14 and 28 days;treatment of rats with Madopar at 28 days suppressed microglial activation.Treatment of rats with gastrodin or Madopar at 28 days significantly reduced interleukin-1β expression.The loss of substantia nigral dopaminergic neurons paralleled the microglial activation in Parkinson’s disease model rats treated with rotenone.The inflammatory factors tumor necrosis factor-α and interleukin-1β are involved in the substantia nigral damage.Gastrodin could protect dopaminergic neurons via inhibition of interleukin-1β expression and neuroinflammation in the substantia nigra.     

Cortical regulation of striatal projection neurons and interneurons in a Parkinson's disease rat model

Striatal neurons can be either projection neurons or interneurons, with each type exhibiting distinct susceptibility to various types of brain damage. In this study, 6-hydroxydopamine was injected into the right medial forebrain bundle to induce dopamine depletion, and/or ibotenic acid was injected into the M1 cortex to induce motor cortex lesions. Immunohistochemistry and western blot assay showed that dopaminergic depletion results in significant loss of striatal projection neurons marked by dopamine- and cyclic adenosine monophosphate-regulated phosphoprotein, molecular weight 32 k Da, calbindin, and μ-opioid receptor, while cortical lesions reversed these pathological changes. After dopaminergic deletion, the number of neuropeptide Y-positive striatal interneurons markedly increased, which was also inhibited by cortical lesioning. No noticeable change in the number of parvalbumin-positive interneurons was found in 6-hydroxydopamine-treated rats. Striatal projection neurons and interneurons show different susceptibility to dopaminergic depletion. Further, cortical lesions inhibit striatal dysfunction and damage induced by 6-hydroxydopamine, which provides a new possibility for clinical treatment of Parkinson's disease.     

Curcumin protects against staurosporine toxicity in rat neurons

Objective Curcumin is extracted from the turmeric plant (Curcuma longa Linn.) and is widely used as a food additive and traditional medicine. The present study investigated the activity of curcumin against staurosporine (STS) toxicity in cell culture. Methods Rat hippocampal neurons in primary culture were exposed to STS (20 μmol/L) and treated with curcumin (20 μmol/L). Cell viability was tested by MTT assay and reactive oxygen species (ROS) were measured using the MitoSOX red mitochondrial superoxide indicator. Western blot was used to assess changes in the levels of caspase-3 (Csp3), heat shock protein 70 (Hsp70) and Akt. Results The results showed that curcumin protects against STS-induced cytotoxicity in rat hippocampal neurons. Csp3, Hsp70, Akt and ROS activation may be involved in this protection. Conclusion Curcumin could be a potential drug for combination with STS in cancer treatment to reduce the unwanted cytotoxicity of STS.     

Nigral dopaminergic neuron replenishment in adult mice through VE-cadherin-expressing neural progenitor cells

The function of dopaminergic neurons in the substantia nigra is of central importance to the coordination of movement by the brain’s basal ganglia circuitry.This is evidenced by the loss of these neurons,resulting in the cardinal motor deficits associated with Parkinson’s disease.In order to fully understand the physiology of these key neurons and develop potential therapies for their loss,it is essential to determine if and how dopaminergic neurons are replenished in the adult brain.Recent work has presented evidence for adult neurogenesis of these neurons by Nestin~+/Sox2~–neural progenitor cells.We sought to further validate this finding and explore a potential atypical origin for these progenitor cells.Since neural progenitor cells have a proximal association with the vasculature of the brain and subsets of endothelial cells are Nestin~+,we hypothesized that dopaminergic neural progenitors might share a common cell lineage.Therefore,we employed a VE-cadherin promoter-driven CRE~(ERT2):TH~(lox)/TH~(lox) transgenic mouse line to ablate the tyrosine hydroxylase gene from endothelial cells in adult animals.After 26 weeks,but not 13 weeks,following the genetic blockade of tyrosine hydroxylase expression in VE-cadherin~+cells,we observed a significant reduction in tyrosine hydroxylase~+neurons in the substantia nigra.The results from this genetic lineage tracing study suggest that dopaminergic neurons are replenished in adult mice by a VE-cadherin~+progenitor cell population potentially arising from an endothelial lineage.     

Zhichan decoction induces differentiation of dopaminergic neurons in Parkinson’s disease rats after neural stem cell transplantation

The goal of this study was to increase the dopamine content and reduce dopaminergic metabolites in the brain of Parkinson’s disease rats. Using high-performance liquid chromatography, we found that dopamine and dopaminergic metabolite（dihydroxyphenylacetic acid and homovanillic acid） content in the midbrain of Parkinson’s disease rats was increased after neural stem cell transplantation ＋ Zhichan decoction, compared with neural stem cell transplantation alone. Our genetic algorithm results show that dihydroxyphenylacetic acid and homovanillic acid levels achieve global optimization. Neural stem cell transplantation ＋ Zhichan decoction increased dihydroxyphenylacetic acid levels up to 10-fold, while transplantation alone resulted in a 3-fold increment. Homovanillic acid levels showed no apparent change. Our experimental findings show that after neural stem cell transplantation in Parkinson’s disease rats, Zhichan decoction can promote differentiation of neural stem cells into dopaminergic neurons.     

还原型谷胱甘肽减轻6-羟基多巴胺对骨髓基质细胞的毒性损伤作用

We studied the effect of reduced glutathione on bone marrow stromal cells (BMSCs) treated with 6-hydroxydopamine (6-OHDA), which shows a toxic effect on dopaminergic neurons. The proliferation of BMSCs treated with 6-OHDA decreased, while that of BMSCs treated with reduced glutathione increased. The proliferation of BMSCs treated with both 6-OHDA and reduced glutathione was significantly higher compared with that treated with 6-OHDA alone. These findings indicate that reduced glutathione alleviates the toxic effect of 6-OHDA on BMSCs.     

The experimental study of the damage of environmental neurotoxins on the cultured rat dopaminergic neurons

Objective To establish the culture system of rat dopaminergic neurons. and to determine whether Paraquat and Dieldrin selectively destroy cultured rat dopaminergic neurons respectively. Methods The cultured rat dopaminergic neurons were treated for 24h with Paraquat and Dieldrin(0.001 to 100 μ mol/L) respectively, Data were expressed as percentage of surviving TH-positive(TH+) cells and other cells per culture dish. Results Paraquat was not effective in selectively destroying TH+ neurons. Dieldrin (1 μ mol/L) selectively decreased the number of TH+ neurons without affecting other cells. The EC50 of Dieldrin on TH+ neurons was 27.6 l mol/L. Conclusion: Paraquat can not selectively destroy dopaminergic neurons in culture. Dieldrin (1 μ mol/L) can selectively destroy the dopaminergic neurons in culture, which make it a potential etiological agent for PD. The possible parkinsonogenic effect of Dieldrin is deserved for further investigation.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

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

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 University 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 mesenceDhalon 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 iniected with 3 μ L cell suspension containing dopaminergic neurons difierentiated from neural stem cells.The dopaminergic neurons PNS group received 3 μ L 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 operation(P<0.0 1).Rotational asymmetry was fugher 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.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

Inhibition of Autophagy by Estradiol Promotes Locomotor Recovery after Spinal Cord Injury in Rats

17β-estradiol(E2) has been shown to have neuroprotective effects in different central nervous system diseases. The mechanisms underlying estrogen neuroprotection in spinal cord injury(SCI) remain unclear. Previous studies have shown that autophagy plays a crucial role in the course of nerve injury. In this study, we showed that E2 treatment improved the restoration of locomotor function and decreased the loss of motor neurons in SCI rats. Realtime PCR and western blot analysis revealed that the protective function of E2 was related to the suppression of LC3 II and beclin-1 expression. Immunohistochemical study further confirmed that the immunoreactivity of LC3 in the motor neurons was down-regulated when treated with E2. In vitro studies demonstrated similar results that E2 pretreatment decreased the autophagic activity induced by rapamycin(autophagy sensitizer) and increased viability in a PC12 cell model. These results indicated that the neuroprotective effects of E2 in SCI are partly related to the suppression of excessive autophagy.