Minocycline accelerates recovery of sickness behavior score in septic rats

Objective: This study evaluated whether sickness behavior score (SBS) reflects neurochemical alterations and memory impairment in septic rats, and whether microglial activation contributes to these outcomes. Methods: Forty-eight male, 60-day-old Wistar rats (300–350 g) were evaluated daily after induction of sepsis by cecal ligation and perforation (CLP) or laparotomy (sham) in order to determine the involvement of microglial activation in the SBS. Animals received minocycline, an inhibitor of microglial activation, prior to surgery. Oxidative stress, IL-6 levels, markers of the hypothalamic–pituitary–adrenal axis, BDNF, and behavior were determined ten days after CLP. Results: The CLP + minocycline group showed a faster reduction in SBS (p < 0.001). Chronic sickness behavior was associated with brain levels of IL-6, nitrite/nitrate, and Brain-Derived Neurotrophic Factor (BDNF) and poorer performance on inhibitory avoidance behavioral tests (p < 0.05). Conclusion: Microglial activation and neuroinflammation occurring in sepsis may contribute to higher SBSs, reinforcing the score’s use to predict systemic and central septic severity.