Study of Microglia/Macrophages Activation Using Systemic Administration of Valproic Acid as A Histone Deacetylase Inhibitor

The aim of this study was to evaluate the effect of Valproic acid (VPA) as a histone deacetylase inhibitor on decrease of microglia /macrophage activaty and nervous tissue destruction after spinal cord injury of rat (SIC). To SCI, contusion model was used. Ten contused rats were equally divided into two groups. Control group did not receive any injection and treatment group received valproic acid (400 mg/kg) intraperitoneally daily for two weeks. Rats were killed at 28 days post injury then damaged spinal cord was removed and examined for H4 acetylation, ED-1 and OX-42 positive cells using immunohistochemistry procedure. Also the cavity volume percentage in 4200 μm length of the spinal cord (central, rostral and caudal regions from the injury epicenter) was assessed for each sample. Results showed increases of histone H4 acetylation and decreases of ED-1 (lysosomal marker) and OX-42 (microglia marker) positive cells. Also the percentage of cavity volume in valproic acid-treated group compared to control (untreated) showed significant decreases. Prescription of valproic acid in the early stages of SIC decreases microglia/macrophages activity, and neural tissue damage in a spinal cord injury model.