| Objective: To explore the neuroprotection of Copolymer-1 (Cop-1) immunity or adoptive transfer of Cop-1 specific lymphocytes in MPTP-intoxicated acute or chronic C57BL/6J mice. Methods: The mice parkinson's disease (PD) models was prepared by acute or chronic administration of MPTP in male C57BL/6J mice (weight 20~25 g).1. Chronic PD model: The mice were randomly divided into 5 groups, namely MPTP model control group, normal control group, Cop-1 pre-immunity group (animals were immunized with Cop-1 7 days before MPTP treatment), Cop-1 post-immunity group (animals were immunized in 7 days after MPTP treatment), and Cop-1 immunity group (animals were injected with MPTP immediately after Cop-1 immunity). The mice except normal control group received one i.p. MPTP (5mg/kg) injection every day. 24 days after continuous MPTP treatment, all mice were killed after 7 days of last MPTP injection. The morphologic changes of spleens were analyzed using HE staining. The dopaminergic neurons were analyzed quantitatively using immunohistocheministry of tyrosine hydroxylase (TH) and stereological counts. The contents of DA and its metabolits, such as DOPAC and HVA, in stratum were assayed using HPLC. To observe that whether Cop-1 could protect DA neurons by immunization in the C57BL/6J mouse.2. Acute PD model: 20 ~ 25g of normal male C57BL/6J mice were divided randomly into Cop-1 immunized, Cop-1 antigen-specific lymphocyte adoptive transfer, MPTP model control and normal control groups. The animals of immunized group were immunized with Cop-1 10 days before MPTP injection; the animals of transfer group received adoptive transfers of Cop-1 antigen-specific lymphocytes immediately after MPTP injection. The mice except normal control group received four i.p. injections at 2 hours intervals of MPTP (18mg/kg), the normal control group animals received only saline injections. For adoptive transplantation, the donor female C57BL/6J mice were immunized with 200μg Cop-1 (emulsified with complete Freund's adjuvant in equal) to female C57BL/6J mice as the donor cells to carry out transplantion. The Cop-1 specific lymphocytes were isolated and cultured, identified, marked and counted, and 5×107 cells were transferred to the recipients immediately after last MPTP injection. All animals were sacrificed after 7 days of last MPTP injection. The dopaminergic neurons were analyzed quantitatively using immunohistocheministry of tyrosine hydroxylase (TH) and stereological counts. The protective effects of Cop-1 immunity or Cop-1 specific lymphocytes to dopaminergic neurons in substantia nigra (SN) were evaluated by comparison of the difference of numbers of dopaminergic (DA) neurons among groups.Results: 1. In the chronic model, compared with normal control group, the spleens appearance from other groups appear dark, but no abvious morphologic change was observed in HE staining. The quantitative analysis of TH-positive neurons in SN indicated that the chronic MPTP treatment resulted a 65.13% loss of DA neurons in SN of MPTP control animals compared with normal control, and the loss in Cop-1 pre-immunity group, Cop-1 post-immunity group, and Cop-1 immunity group were 28.29%, 31.68%, and 27.55% separately compared to normal control group. The numbers of DA neurons in the animals of all groups treated with Cop-1 were significantly higher than the MPTP model control group. HPLC results revealed that the content of DA and its metabolitic in striatum of MPTP model control were obviously lower than other groups, otherwise, although the contents in Cop-1 treatment groups were lower than nomorl control group, significantly higher than MPTP control group. treatment caused a 58.02% loss of TH-positive neurons in SN compared to saline control group. In contrast, MPTP-injected mice that received Cop-1 immunity or Cop-1 specific lymphocytes exhibited a much smaller reduction in the number of TH-positive neurons compared with MPTP animals. It is suggested that Cop-1 immunity or Cop-1 specific lymphocytes transfer might have a protective effect to DA neurons in the SN of MPTP-intoxicated mice.Conclusions: 1. In the chronic model: The present results proved that the continuous low dosage MPTP injection couldn't result in an obviously damaged to the immune system in chronic MPTP treatment C57BL/6J mice. Cop-1 immunity could attenuate MPTP-mediated nigrostriatal DA neurodegeneration in the chronic PD mice.2. In the acute model: The present data suggested that Cop-1 pre-immunity or Cop-1 specific lymphocytes adoptive transfer could against MPTP toxicity and protect the DA neurons in SN of C57BL/6J mice with acute MPTP treatment. The equal protective effects between Cop-1 pre-immunity and Cop-1 specific lymphocytes adoptive transfer implied that the Cop-1 specific lymphocytes play a mainly role in the protective process of Cop-1 immunity. It suggested that Cop-1 immunity might be a new potential PD therapeutic strategy. 2. In the acute model, stereological counts revealed that MPTP... |
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