Dynamic levels and significance of the triggering receptor expressed on myeloid cells-1 expression in injury brain tissues of rat caused by pneumolysin

Abstract

Objective To investigate the dynamic level changes and significance of triggering receptor expressed on myeloid cells-1 (TREM-1) in the injury brain tissues of rats caused by pneumolysin (PLY). Methods Sixty-four SD rats were randomly and equally divided into PLY group and control group, 0.1 mL PLY and isopyknic normal saline was given through left internal carotid artery respectively.Brain tissue gross and histological changes were observed at different time(4 h, 6 h, 12 h, 24 h), meanwhile the expression levels of neurocyte damage marker glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE) protein were detected by immunohistochemistry; and the expression levels of TREM-1, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were detected respectively by enzyme-linked immunosorbent assay. Results The observation of brain tissue gross and histological changes indicated the existence of brain injury, and the expression levels of GFAP, NSE, TNF-α and IL-6 protein increased from 4 h after PLY were injected and augmented dynamically as time went on, compared with the control group at correspon-ding time points, the differences were statistically significant(all P 0.05). Conclusions The expression levels of TREM-1 up-regulated obviously in the early stage of brain damage induced by PLY, which might be involved in the pathological process of brain damage by promoting the expression of TNF-α and IL-6. Key words: Pneumolysin; Infectious brain injury; Inflammation; Triggering receptor expressed on myeloid cells-1