The effects of early maternal separation on gastric mucosa maturation and stress response (LB739)

Abstract

Repeated maternal separation (MS) is a potent and chronic stressor that activates the HPA axis response. We demonstrated that few hours of fasting elevate plasma corticosterone (CORT) in pups, but it also increases CBG binding and reduces glucocorticoid receptor (GR) intracellular traffic in the gastric epithelium. In the stomach, complete cell differentiation occurs by the third postnatal week, in parallel with plasma CORT augment. However, it is not clear how CORT and maternal separation affect gastric epithelium growth and maturation. Currently, our aims were to evaluate: the impacts of MS on body weight; total CORT plasma levels by RIA; gr expression, and the consequences on rat gastric mucosa cell differentiation through the evaluation of developmental target genes by qPCR. For this purpose we used 10, 14, 18, 21 and 30‐ day‐ old rats divided into two groups: 1) Maternal separated group (MS) in which pups were removed from their dams and placed in a clean cage (32° C) for 3 h/day (from postnatal day 2‐ 21),; 2) Control group (C), in which pups were equally manipulated, but were maintained with the dams until weaning (21 days). MS resulted in loss of body weight in the developing rats (p <0.05), but such difference did not persist until 30‐ d‐old rats. Total CORT levels increased only in 18‐ and 30‐d‐old MS rats (p< 0.05).gr expression was down‐ regulated by MS only in 18‐ d‐ old pups (p <0.05). Mucin 6 expression increased after MS in 18‐ and 30‐ d‐ old rats, but decreased at 21 days (p <0.05). Mist1 increased only in 18‐ and 30‐d‐old rats (p <0.05), while Pepsinogen C expression was amplified only in 18‐ d‐old MS pups (p <0.05). In conclusion, repeated MS during early postnatal life reduced body mass, altered total CORT plasma levels and modified the profile of gastric genes expression throughout postnatal development.Grant Funding Source: Supported by Grant 2011/17415‐3 and 2012/10948‐9, São Paulo Research Foundation (FAPESP)