Expression Of Peroxiredoxin 1 After Traumatic Spinal Cord Injury In Rats

Objective1.To investigate PRDX1 expression and distribution in spinal cord injury model of adult rat.2.To judge the relationship between PRDX1 and glia cell proliferation,we examine PCNA protein expression with or without LPS treatment after PRDX1 silencing by western blot.Methods1.We performed spinal cord injury in improved Allen's method at T9 in adult Sprague Dawley(SD)rats.Than we used Western blot,immunohischemistry staining,double immunofluorescene staining techniques to investigate the expression level,distributiongs and cellular location of PRDX1.2.To further investigate its function in glia cell proliferation,we knocked down PRDX1 in astrocytes and microglia in vitro.PRDX1 siRNA,nonspecific siRNA,and negative control were tested 48 h after transfection.ResultsWestern blot analysis showed that PRDX1 expression was low in the sham group,while it increased from 6 h to 5 days and then gradually dropped after SCI.The date of immunohistochemistry staining demonstrated that PRDX1 was detected in the rostral spinal cord at 2 mm from the epicenter in both sham and injury groups.PRDX1 was expressed in white matter but not in gray matter.PRDX1 was mainly expressed in glial cells but barely in neurons according to the positive cell profiles in both the sham and SCI groups.According to the result of immunostaining staining,PRDX1 was expressed in astrocytes and microglia.There was no PRDX1 expression in neurons.Additionally,astrocytes and microglia expressing PRDX1 increased after SCI,and furthermore PRDX1 expression apparently increased in astrocytes andmicroglia in the injury group compared to the sham group.We performed double-labeled immunofluorescent staining to detect the distribution of PRDX1,GFAP,CD11 b,and PCNA in rat spinal cord.PCNA expression was low in the sham group.However,PCNA significantly increased and colocalized with PRDX1,GFAP,and CD11b(Fig.5i,n)in white matter at 5 days after SCI.Furthermore,we had performed triple labeling and found the colocalization of GFAP,PCNA,and PRDX1.To judge the relationship between PRDX1 and glia cell proliferation,we examine PCNA protein expression with or without LPS treatment after PRDX1 silencing by western blot.PCNA was reduced remarkably after treating PRDX1 knock down astrocytes and microglia with LPS for 12 h.Conclusions The results of this research suggested that PRDX1 might play a crucial role in astrocyte and microglia proliferation after SCI.