Exercise and crocin prevent adolescent-stress induced impairment of spatial navigation and dendritic retraction in the hippocampal CA3 area in adult male rats.

Adolescent chronic stress has been shown to induce functional, biochemical and morphological modifications of the hippocampus, leading to stress-related disorders in adulthood. The present study investigated the effects of exercise, crocin and their combination on spatial learning and memory impairment and dendritic retraction of the CA3 pyramidal neurons induced by chronic adolescent stress in adult male rats. Rats were exposed to restraint stress 2 h/day for 10 days during postnatal days (PNDs) 30-40. Following this period, separate groups of animals were treated with crocin (25 and 50 mg/kg), exposed to running wheel, and or received the combined treatment during PNDs 41-55. Following the interventions, plasma levels of corticosterone, spatial learning and memory, apical dendritic length of CA3 pyramidal neurons and BDNF levels in the CA3 area were assessed. Findings showed that adolescent stress significantly increased corticosterone levels and caused a tendency to reduce CA3 BDNF levels. Adolescent stress also impaired spatial learning and memory, and retracted apical dendritic length of CA3 pyramidal neurons. Crocin, voluntary exercise, and their combination recovered stress-induced spatial learning and impairment and CA3 pyramidal neurons dendritic length retraction. All treatments also reduced significantly corticosterone levels and enhanced CA3 BDNF levels in the stress groups. Finally, these treatments even increased apical dendritic length of CA3 pyramidal neurons in the non-stress groups. These findings indicate that detrimental effects of adolescent stress on cognitive function and hippocampal morphology in adulthood could be restored by early interventions with physical activity and crocin treatment during adolescent period.

Beneficial Effects of Physical Activity and Crocin Against Adolescent Stress Induced Anxiety or Depressive-Like Symptoms and Dendritic Morphology Remodeling in Prefrontal Cortex in Adult Male Rats.

Increasing evidence suggests that exposure to chronic stress during adolescent period may lead to behavioral and neuronal morphology deficits in adulthood. This study examined whether crocin, the main active saffron constituent, and voluntary exercise, alone or combined, could prevent the detrimental influences of chronic restraint stress during adolescent (postnatal days, PND, 30-40) on behavioral and morphological deficits in adult (PND60) male rats. Results showed that plasma corticosterone levels increased at PND40, but not PND60 in stressed rats. Moreover, stressed rats demonstrated enhanced anxiety levels and depression like behaviors in adulthood. These behavioral abnormalities were accompanied by a decline in apical dendritic length in both infralimbic and prelimbic regions and dendritic branches in infralimbic region of the prefrontal cortex. Treatment with crocin, exposure to wheel running activity, and the combined interventions alleviated both behavioral and morphological deficits induced by adolescent stress. Moreover, these treatments exerted positive neuronal morphological effects in the prefrontal cortex in non-stressed animals. Our findings provide important evidences that exercise as a non-pharmacological intervention and crocin treatment during pre-pubertal period can protect against adolescent stress induced behavioral and morphological abnormalities in adulthood.

Contribution of estrogen receptors alpha and beta in the brain response to traumatic brain injury.

OBJECT: Although there is evidence that estradiol has neuroprotective effects after traumatic brain injury (TBI) in female rats, it is unclear which estrogen receptor (ER) subtype, ERα or ERß, mediates this effect. The authors therefore examined the roles of the different ERs in this effect. Here the authors used the ERα selective agonist propyl pyrazole triol (PPT) and the ERß selective agonist diarylpropionitrile (DPN) alone and in combination in female rats to investigate this question. METHODS: Before the ovariectomized animals were injured using the Marmarou TBI technique, they were randomly divided into the following 9 groups: control, sham, TBI, vehicle, E1 (physiological dose of 17-ß estradiol), E2 (pharmacological dose of 17-ß estradiol), PPT, DPN, and PPT+DPN. Levels of blood-brain barrier (BBB) disruption (5 hours) and water content (24 hours) were evaluated after TBI. In groups receiving drugs or vehicle, treatment was administered as a single dose intraperitoneally 30 minutes after induction of TBI. RESULTS: Results showed that brain edema or brain water content after TBI was lower (p < 0.001) in the E2, PPT, DPN, and PPT+DPN groups than it was in the vehicle group. After trauma, the Evans blue dye content or BBB permeability was significantly higher in the TBI and vehicle groups (p < 0.001) than in the E2, PPT, DPN, and PPT+DPN groups. The inhibitory effects of PPT+DPN on brain water content, neurological scores, and Evans blue dye content were the highest for all groups. Although both PPT and DPN increased neurological scores after TBI, PPT appears to be more effective in increasing neurological scores. CONCLUSIONS: Neuroprotective effects of estradiol on brain edema, BBB permeability, and neurological scores are mediated through both ERα and ERß. This may suggest a therapeutic potential in the brain trauma for ER-specific agonists.