Objective To reveal the damaging effects of subacute manganese exposure-induced microglia on the central nervous system of mice,and to elucidate the key role and mechanism of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3(NLRP3)inflammasome.Methods C57BL/6 mice and NLRP3-/-mice were randomly divided into 2 groups,respectively,with a total of 4 groups(12 mice in each group):control group,manganese group(Mn group),NLRP3-/-group,and NLRP3-/-+Mn group.Mn group and NLRP3-/-+Mn group were exposed to manganese using subcutaneous injection(100 mg/kg)on day 1,4,7,10,and 13.Control group and NLRP3-/-group were given the same volume of normal saline.Behavioral tests were used to observe the changes in motor ability of mice;immunohistochemical TH staining was used to observe the morphological changes of neurons in the brain tissue of mice;blood manganese levels of mice in each group were detected by atomic absorption spectrophotometry;mRNA expression levels of microglia activation-related markers IL-18 and IL-1β were detected by qRT-PCR;and the activation of microglia in the striatum was detected by immunofluorescence staining.Western blotting was used to detect the expression of NLRP3-related proteins NLRP3,Caspase-1,IL-18,and IL-1β.Results Compared with the control group,mice in the Mn group showed significantly lower motor coordination ability(P＜0.05),significantly lower number of neuronal cells in the substantia nigra(P＜0.05),significant activation of microglia(P＜0.05),and increased protein expression levels of NLRP3 and its related molecules NLRP3,Caspase-1,IL-18,and IL-1β(P＜0.05).After NLRP3 knockout,the decrease in motor coordination ability induced by manganese exposure in mice was significantly rebounded(P＜0.05),and the neuronal damage,microglia activation,and increased expression of NLRP3-related proteins induced by manganese exposure could be reversed(P＜0.05).Conclusion Manganese exposure may induce microglia activation in the striatal region of mice and promote neurological impairment.Specific knockout of NLRP3 gene can inhibit microglia activation and neurological impairment induced by manganese exposure,and play a significant neuroprotective role.
维普
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