Abstract:

BACKGROUND: Studies have confirmed that localized activation of microglia, however, has been implicated in the pathogenesis of a number of neurological diseases and disorders, such as multiple sclerosis and periventricular leukomalacia (PVL).
OBJECTIVE: To explore the toxicity of lipopolysaccharide (LPS)-induced activated-microglia to oligodendrocyte precursor cells.
METHODS: Co-cultured microglias and oligodendrocyte precursor cells obtained from two-day-old Sprague-Dawley rats were divided into the co-cultured control group and the co-cultured LPS group. After co-cultured cells were induced by LPS (100 μg/L) for 48 hours, the concentration of nitric oxide was measured by nitric acid-deoxidize colorimetry; the generated levels of (O₂^-) were determined by deoxidize colorimetry; the levels of peroxynitrite (ONOO^-) were detected by immunocytochemistry. The morphologic changes of death oligodendrocyte precursor cells were observed using Hoechst 33342/propidium iodide staining and the survival rate of oligodendrocyte precursor cells was detected by flow cytometry.
RESULTS AND CONCLUSION: Compared with co-cultured control group, the levels of nitric oxide, O₂^-and ONOO^- increased significantly in co-cultured LPS group, and with a higher apoptotic rate of oligodendrocyte precursor cells. It is validated in vitro that the death pathway of LPS-induced activated-microglia to oligodendrocyte precursor cells involves in LPS-induced microglia activation, impels microglia to express inducible nitric oxide synthase and to activate NADPH oxidase, results in the overproduction of nitric oxide and O₂^- , which further forms ONOO^-, a primary toxic factor to oligodendrocyte precursor cells, finally leads to oligodendrocyte precursor cells death.