Environmental enrichment promotes robust functional and histological benefits in female rats after controlled cortical impact injury

Abstract

Environmental enrichment (EE) consistently induces marked benefits in male rats after traumatic brain injury (TBI), but whether similar efficacy extends to females is not well established. Hence, the aim of this study was to reassess the effect of EE on functional and histological outcome in female rats after brain trauma. Twenty-four normal cycling adult female rats underwent verification of estrous stage prior to controlled cortical impact (CCI) or sham injury and then were assigned to EE or standard (STD) housing. Motor function was assessed with beam-balance/beam-walk and rotarod tasks on post-operative days 1–5 and every other day from 1–19, respectively. Spatial learning/memory was evaluated in a Morris water maze on days 14–19. Morphologically intact hippocampal CA 1/3 cells and cortical lesion volume were quantified 3 weeks after injury. No differences were observed between the EE and STD sham groups in any endpoint measure and thus the data were pooled. In the TBI groups, EE improved beam-balance, beam-walk, rotarod, and spatial learning performance vs. STD (p’s < 0.05). EE also provided significant histological protection as confirmed by increased CA1/3 cell survival and decreased cortical lesion size vs. STD. These data demonstrate that EE confers robust benefits in female rats after CCI injury, which parallels numerous studies in males and lends further credence for EE as a preclinical model of neurorehabilitation.

A Combined Therapeutic Regimen of Buspirone and Environmental Enrichment Is More Efficacious than Either Alone in Enhancing Spatial Learning in Brain-Injured Pediatric Rats

“…[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]36 EE alone, however, did not lead to an increase in memory retention, which is in contrast to that seen in adult models. 23,26,29,33 As reported for Experiment 1, the buspirone (0.1 mg/kg) STD-housed group was also significantly better than the STD vehicle group in the MWM. The data also showed that the combination group (buspirone, 0.1 mg/ kg + EE) performed markedly better than the single therapy groups (i.e., EE plus vehicle and STD buspirone) in both the acquisition of spatial learning and memory retention, which suggests an additive effect.…”

“…[18][19][20][21][22][23][24][25][26] Likewise, EE has also been shown to confer neurobehavioral and histological benefits in adult male rats after CCI 20,23,[26][27][28][29][30][31][32][33][34] and fluid percussion brain injury. [35][36][37][38][39][40] Recently, the benefits of EE have also been extended to female rats after CCI.…”

“…[35][36][37][38][39][40] Recently, the benefits of EE have also been extended to female rats after CCI. 33 Despite the consistent benefits produced by these therapies in adult rodent models of TBI, they have received limited attention in pediatric studies. Determining potentially efficacious therapies for pediatric TBI, which often result from falls or sportsrelated activities, is of great concern because it is the leading cause of death and disability in this age population.…”

“…Environmental enrichment (EE), in particular, has been evaluated extensively in adult, and to a much lesser extent, in pediatric rodents as a pre-clinical model of neurorehabilitation. EE consists of expansive accommodations, which include cognitive and social stimulation that results in the reduction of histological damage and enhancement of functional recovery 27 induced by either controlled cortical impact (CCI) 20,23,[26][27][28][29][30][31][32][33][34] or fluid percussion. [35][36][37][38][39][40] Given that the 5-HT 1A receptor agonist buspirone and EE confer recovery in adult rats after brain trauma, the goals of this study were to evaluate the potential efficacy of these therapies alone and in combination after pediatric TBI.…”

Can Soy Diet be Protective in Severe and Diffuse Traumatic Brain Injury?

“…Rats were trained prior to TBI or sham surgery to perform the task without error (i.e., traverse the beam under 5 s). Task of BW was assessed before trauma, and on D0, D1 and D2 post-TBI that consisted of three trials for any time evaluated [30]. Data for each time were the mean of three trials.…”