Millions of persons every year are affected by traumatic brain injury (TBI), and currently no therapies have shown efficacy in improving outcomes clinically. Recent research has suggested that enriched environments (EE), embryonic neural stem cells (eNSC), and progesterone (PROG) improve functional outcomes after TBI, and further, several investigators have suggested that a polytherapuetic approach may have greater efficacy than a single therapy. The purpose of the current study was to determine if varying combinations of post-injury EE, progesterone therapy, or eNSC transplantation would improve functional outcomes over just a single therapy. A controlled cortical impact was performed in rats to create a lesion in the medial frontal cortex. The rats were then placed in either EE or standard environments and administered 10 mg/kg progesterone or vehicle injections 4 h post-injury and every 12 h for 72 h after the initial injection. Seven days after the surgery, rats were transplanted with either eNSCs or media. Rats were then tested on the open field test, Barnes maze, Morris water maze, and Rotor-Rod tasks. Improved functional outcomes were shown on a majority of the behavioral tasks in animals that received a combination of therapies. This effect was especially prominent with therapies that were combined with EE. Immunohistochemistry showed that the transplanted eNSCs survived, migrated, and displayed neural phenotypes. These data suggest that a poly-therapeutic approach after TBI improves functional recovery to a greater magnitude. Moreover, when polytherapies are combined with EE, the effects on recovery are enhanced, leading to greater recovery of function.
Keywords: TBI; eNSC; enriched environment; progesterone.