Efficacy of Minocycline in Female Rats after Mild Diffuse Traumatic Brain Injury
Friday, September 18, 2015 — Poster Session V
- NR Jikaria
- LC Turtzo
- J Lescher
- W Tu
- JA Frank
Objective: To examine the efficacy of minocycline in female rats in a diffuse injury model of traumatic brain injury (TBI) Background: Minocycline is an antibiotic with reported anti-inflammatory properties in stroke and some models of TBI. To date, studies of minocycline in TBI have been performed in male animals, and whether minocycline is effective in females after TBI is unknown. Design/Methods: Female Sprague-Dawley rats (n=16) experienced a mild diffuse TBI using a closed head weight drop model (450g weight/2m height). Rats were treated with either minocycline 100 mg/kg (n=8) in PBS or PBS (n=8) via intraperitoneal injection on days 0, 1, and 2 post-injury. At 16 days post-injury, perfused brains were collected for ex vivo MRI and immunohistochemical (IHC) analysis to assess microglial activation (via Iba1) and astrocytosis (via GFAP). Brains from uninjured rats (n=3) were also analyzed. Results: There were no statistically significant quantitative differences in degree of Iba1 staining in cortex (% region of interest (ROI) Iba1 mean±SD: minocycline=1.06±0.06; saline=1.2±0.2; naïve control=1.0±0.2) or in corpus callosum (CC) (% ROI Iba1 minocycline=1.5±0.3; saline=1.9±0.6; naïve control=1.00±0.01) regardless of treatment group. Likewise, there were no statistically significant differences in GFAP staining by treatment group in cortex (% ROI GFAP minocycline=1.3±0.8; saline=1.5±0.9) or in CC (% ROI GFAP minocycline=2±1; saline=2±1). Conclusions: Treatment of female Sprague-Dawley rats with minocycline versus saline did not result in significant differences in microgliosis or astrogliosis at Day 16 post-injury as assessed by IHC. This contrasts with the reported efficacy of minocycline in male rodents after focal TBI.