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The Effect of Maternal Separation and Early Environmental Enrichment on the Rat Colon
Author(s) -
ColónEchevarría Claudia,
Cruz Myrella L,
Doreste Raura,
TorresReveron Annelyn,
Appleyard Caroline B
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.lb693
Subject(s) - environmental enrichment , crypt , inflammation , medicine , irritable bowel syndrome , open field , maternal deprivation , physiology , endocrinology , chronic stress
Background Early life stress has been associated with increasing the risk of developing gastrointestinal disorders by disrupting the brain‐gut axis function. Maternal separation (MS) in rats is a well‐studied model of early life stress and has been linked to inflammation in adulthood in conditions such as inflammatory bowel disease and irritable bowel syndrome. Environmental enrichment (EE) has been hypothesized to prevent the damaging effects of stress exposure by stabilizing the hypothalamic‐pituitary‐adrenal axis but there is no timeframe yet established to pinpoint when this treatment is more effective. Aim Investigate whether maternal separation causes intestinal inflammation and whether early environmental enrichment can reverse any alterations. Methods Sprague‐Dawley rat pups (both male and female, n=4–6/treatment group/gender) were separated from the mother for 3 hours/day from postnatal day one until 21 days of age. Rats were kept in either standard housing or environmental enrichment boxes, until postnatal day 78 when forced swim and open field‐testing were performed before sacrifice. Colon tissues were removed and paraffin embedded, after which microscopic scoring, crypt length and mast cell counts were evaluated. Results MS caused an increase in microscopic colon damage compared to normal controls (not exposed to MS or EE) in both females (p<0.05) and males (p<0.001). MS animals also had longer crypt length and increased mast cells. Males showed greater damage than female rats after MS protocol and EE, however enriched males showed a decrease in depressive‐like behaviors while enrichment did not have any effect in females. The early environmental enrichment did not reverse the damage caused in maternally separated rats but tended to decrease mast cell infiltration. Conclusion MS caused inflammation in the colonic tissue, which was not attenuated by early EE. Damage to the mucosal barrier by MS may be due to loss of tight junction proteins. Future studies need to be performed to evaluate the effect of later environmental enrichment on MS rats. Support or Funding Information Supported in part by R25GM082406, K07AT008027, and MD007579 .