Tong E-tang

LPS-induced degeneration of dopaminergic neurons of substantia nigra in rats.

SummaryIn order to investigate the neurotoxicity of lipopolysaccharide (LPS) on the dopaminergic neurons of substantia nigra and the pathogenesis of Parkinson disease. LPS was stereotaxically infused into substantia nigra (SN). At different dosages and different time points with 5 μg LPS, the damage of the dopaminergic neurons in SN was observed by using tyrosine-hydroxylase (TH) immunohistochemical staining. The results showed that 14 days after injection of 0.1 μg to 10 μg LPS into the rat SN, TH-positive (TH+) neurons in the SN were decreased by 5%, 15%, 20%, 45%, 96% and 99% respectively. After injection of 5 μg LPS, as compared with the control groups, TH+ neurons began to decrease at 3rd day and obviously decrease at 14th day, only 5% of total cells, and almost disappeared 30 days later. The results suggested that LPS could induce the degeneration of dopaminergic neurons in the SN in a dose- and time-dependent manner.

Experimental Study on Inhibition of Neuronal Toxical Effect of Levodopa by Ginkgo Biloba Extract on Parkinson Disease in Rats

SummaryIn order to observe neuronal toxical effect of Levodopa and investigate if using Levodopa together with Ginkgo Bilobar Extract (EGb) would be an workable method to treat Parkinson disease, rat models of Parkinson disease (PD) were made by injecting 6-OHDA stereotaxically to right side of the mesencephic ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Rotational behavioral observation, TUNEL, immunocytochemistry, Nissl’s body staining were performed to measure the difference between group treated by Levodopa (50 mg/kg every day for 3 days, 5 days, 7 days, L-dopa group) and group treated by Levodopa combined with EGb (100 mg/kg every day, E-D group). The results showed that in the L-dopa group, the numbers of apoptosis of substantial nigra, rings of rotational behavior were more than those in the E-D group (P<0.05). The numbers of Nissl’s cells in L-dopa group were fewer than in E-D group (P<0.05). The results suggested that Levodopa had neur toxic effect and EGb may decrease the toxicity of levodopa. The combined use of EGb with Levodopa may be a workable method to treat PD and may be better than using Levodopa alone.

Induction of increased intracellular calcium in astrocytes by glutamate through activating NMDA and AMPA receptors.

SummaryTo study the effect of glutamate on the intracellular calcium signal of pure cultured rat astrocytes and the role of NMDA and AMPA receptors in the procedure, the change of calcium signal was investigated by monitoring the fluctuation of intracellular Ca2+ concentration ([Ca2+]i) on the basis of Fura-2 single cell fluorescent ratio (F345/F380). The changes in the effect of glutamate on the intracellular calcium signal were observed after blockage of NMDA and (or) AMPA receptors. It was found that L-glutamate could induce an increased [Ca2+]i in most of the cells in concentration-and time-dependent manner. D-(-)-2-amino-5-phosphonopentanoic acid (D-AP-5, a selective antagonist of the NMDA receptor) and 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX, a selective antagonist of the AMPA receptor) could abolish the effects of NMDA and AMPA respectively. The treatment of D-AP-5 and CNQX simultaneously or respectively could attenuate the effect of L-glutamate at varying degrees. All these indicated that glutamate could modulate intracellular Ca2+ of pure cultured rat astrocytes through different pathways. The activation of NMDA and AMPA receptors took part in the complex mechanisms.

Point Mutation in the Parkin Gene on Patients with Parkinson's Disease

SummaryTo investigate the distribution of possible novel mutations from parkin gene in variant subset of patients with Parkinson’s disease (PD) in China and explore whether parkin gene plays an important role in the pathogenesis of PD, 70 patients were divided into early-onset group and late-onset group; 70 healthy subjects were included as controls. Genomic DNA from 70 normal controls and from those of PD patients were extracted from peripheral blood leukocytes by using standard procedures. Mutations of parkin gene (exon 1–12) in all the subjects were screened by PCR-single strand conformation polymorphism (SSCP), and further sequencing was performed in the samples with abnormal SSCP results, in order to confirm the mutation and its location. A new missense mutation Gly284Arg in a patient and 3 abnormal bands in SSCP electrophoresis from samples of another 3 patients were found. All the DNA variants were sourced from the samples of the patients with early-onset PD. It was concluded that Parkin point mutation also partially contributes to the development of early-onset Parkinson’s disease in Chinese.

Exon deletions of parkin gene in patients with parkinson disease

SummaryMutations in the parkin gene have recently been identified in familial and isolated patients with early-onset Parkinson disease (PD) and that subregions between exon 2 and 4 of the parkin gene are hot spots of deletive mutations. To study the distribution of deletions in the parkin gene among variant subset patients with PD in China, and to explore the role of parkin gene in the pathogenesis of PD, 63 patients were divided into early onset and later onset groups. Exons 1–12 were amplified by PCR, templated by the genomic DNA of patients, and then the deletion distribution detected by agarose electrophoresis. Four patients were found to be carrier of exon deletions in 63 patients with PD. The location of the deletion was on exon 2 (1 case), exon 3 (2 cases) and exon 4 (1 case). All patients were belong to the group of early onset PD. The results showed that parkin gene deletion on exon 2, exon 3 and exon 4 found in Chinese population contributes partly to early onset PD.

Experimental study on heterograft of glomus cells of carotid body for hemiparkinsonian rats.

SummaryTo observe the effects of heterograft of glomus cells of carotid body on hemiparkinsonian rat models, rats with unilateral 6-hydroxydopamine (6-OHDA)-induced lesions of the right dopaminergic neurons of substantia nigra received intrastriatal glomus cells heterograft. Apomorphine-induced rotation was monitored for 30 min at various time points after grafting. The striata were cut and examined for dopamine content by HPLC and for immunohistochemical staining of tyrosine hydroxylase positive neurons (TH+) at the end of the experiments. The results showed that apomorphine-induced rotational behavior was significantly reduced for 12 weeks and the dopamine contents were significantly elevated after grafting (P<0.01), and TH+ cells survived better. The present study demonstrates that intrastriatal heterograft of glomus cells within carotid body in rats with 6-OHDA-elicited lesions could reduce apomorphine-induced rotational behavior and elevate the dopamine contents and numbers of TH+ cell surviving within striatum, and can serve as a new and effective alternative for Parkinson disease.

Experimental Study on the Neuronal Toxical Effect of Levodopa and the Inhibition of Ginkgo Biloba Extract on Parkinson Disease in Rats

Objective: To observe neuronal toxical effect of Levodopa and investigate whether using Levodopa together with EGb is an ideal, workable method to treat Parkinson disease. Methods: In this study, the rat models of Parkinson disease (PD) were made by injecting stereotaxically 6-OHDA to right side of the mesencephic ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). We used rotational behaviour, TUNEL, immunocytochemical, Nissl’s body staining methods to observe the difference between Levodopa (50mg/kg/d×3d, ×5d, ×7d, L-dopa group) and the combination use of Levodopa and EGb (100 mg/kg/d, E-D group). Results: The numbers of apoptosis and rotation, bFGF protein expression in the L-dopa group surpassed those in the E-D group (P<0.05). The number of Nissl cells in the L-dopa group was fewer than the E-D group. Conclusion: Levodopa has neurological toxical effect. EGb may decrease the toxicity of levodopa. The combination use of Ginkgo biloba extract (EGb) and Levodopa is a workable method to treat Parkinson disease and is better than using Levodopa alone.

The effect of beta-amyloid on neurons and the influence of glucocorticoid and age on such effect

SummaryTo explore the relationship between β-amyloid (Aβ) and the pathogenesis of Alzheimer disease (AD), after injection of β-amyloid into the rat brain, the apoptosis of nerve cells and acetylcholine (Ach) content in rat hippocampus were examined by employing TUNEL technique and base hydroxylamine colorimetry respectively. The influence of age and glucocorticoid on the neurotoxic effect of Aβ was also analyzed. Aβ peptide could strongly induce the apoptosis of neurons in hippocampus, cortex and striate body (P<0.05 orP<0.01). In addition, the senility and glucocorticoid pre-treatment could enhance the toxic effect of Aβ(P<0.05 orP<0.01). It is concluded that Aβ may play an important role in the pathogenesis of Alzheimer disease via its induction of apoptosis of neurons and by decreasing the content of the Ach.

Ginkgo Biloba Extract Protects Substantia Nigral Neurons from Apoptosis in PD Rat Model

Purpose: To investigate the apoptotic mechanism during the pathological process of Parkinson disease (PD) and explore the availability of Ginkgo biloba extract (EGb) to cure PD. Methods: Followed 6-OHDA injection stereotaxically to right side of substantia nigra pars compacta(SNc), at the date of 1, 7,14 and 21, we used biochemical, immunohistochemical, TUNEL and electron microscopic techniques to evaluate the level of apoptosis (TUNEL), monitor the degree of oxidative reaction (MDA.SOD), and to observe the change of ultrastructure of substantia nigra in the experimental PD models of rats (PD group), the EGb treatment group (EGb group) and the control group. Results: Contrast to the Control group, the number of apoptotic neurons and free radical level increased in the PD group and the EGb group, but the PD group surpassed the EGb group (p<0.05).In the PD group, the ultrastructure of substantia nigra exhibited the morphological characteristics of apoptosis from 1d to 21d. Conclusions: Free radical insult contributes to the pathological process of PD in rats. EGb may ameliorate the injury of substantia nigra through expiring free radicals during the pathological process of PD in rats.

Experimental Study on Parkinson Disease Model of Rats

Objective: To observe the characteristics of praxiology of Parkinson disease (PD) rats. Methods: At 1d, 7d, 14d after PD rats’ model were successful; we observed the markers of rotational behavior of Parkinson disease (PD) rats. For example: start time, continuous time, maximum turning, etc. Results: From 1d to 14d, PD rats, start time of the rotational behavior elongated gradually, continuous time shortened by degrees, maximum rotational speed and the number of the rotational behavior were invariable. Conclusions: Improved method of PD is scientific, reliable, and simple. Substantial nigral pathology of PD rats makes the foundation of the rotational behavior. The injury of substantial nigral can be reflected by maximum rotational speed and the number of the rotational behavior of PD rats.