The effects of progesterone administration and pre-training on learning & memory, anxiety-like behaviors, and balance impairments following traumatic brain injury in male rats: The role of neuroinflammation.

BACKGROUND: Traumatic brain injury (TBI) is a common complication in human societies. In previous studies, the effects of exercise and sex hormones alone have been shown to prevent the progression of cerebral edema, oxidative stress, and inflammation after traumatic brain injury (TBI). This study investigated the effects of combined progesterone and exercise after TBI in male rats.

METHOD: In this study, 84 rats were divided into 14 groups (7 groups for behavioral tests and 7 groups for evaluating brain water content and molecular and histological parameters, each group containing 6 rats). The study is grouped as follows: 1) Sham, 2) TBI, 3) Vehicle (Veh) (sesame oil, 1 ml/kg intramuscularly), 4) Progesterone (P) (1.7 mg/kg intramuscularly), 5) Exercise (Ex), 6) Exercise with vehicle (Ex +Veh), 7) Exercise and progesterone (Ex +P). The TBI was induced via the Marmarou setup. Finally, at the end of the study, animals were subjected to behavioral tests (Morris water maze, elevated plus maze, and beam walking). Brain water content and cytokine levels were measured after the animals were sacrificed.

FINDINGS: Our results showed that following brain damage, spatial learning, and memory, anxiety, and movement were impaired. Also, the levels of inflammatory cytokines and water content in the animals' brains increased. However, our results showed that prescription of progesterone, exercise, and their combination at all levels could improve the disorders caused.

CONCLUSION: According to our findings, it seems that exercise can be a good substitute for progesterone in the recovery of post-traumatic disorders.