Investigation of the effects of maternal separation on the pancreatic oxidative and inflammatory damages along with metabolic impairment in response to chronic social defeat stress in young adult male rats

Abstract

Chronic glucocorticoid release during the stress response has been proposed to initiate certain damages, which in turn produce metabolic disorders. The present study is the first work to test whether maternal separation (MS) would impact the metabolic alterations associated with pancreatic oxidative and inflammatory damages under chronic exposure to social defeat stress (CSDS) in adulthood. During the first 2 weeks of life, male Wistar rats were exposed to MS or left undisturbed with their mothers (Std). Starting on postnatal day 50, the animals of each group were either left undisturbed in the standard group housing (Con) or underwent CSDS for 3 weeks. Thus, there were 4 groups (n\u2009=\u20097/group): Std-Con, Ms-Con, Std-CSDS, MS-CSDS. Each animal was weighed and then decapitated so that we could collect trunk blood for assessment of fasting plasma corticosterone, insulin, glucose, lipid profile, and insulin resistance. Plasma and pancreatic catalase activity, reduced glutathione (GSH), malondialdehyde levels and pancreatic interleukin-1 beta (IL-1β) content were also measured. MS-CSDS animals showed elevated plasma corticosterone and insulin levels (P\u2009<\u20090.01) along with insulin resistance (P\u2009<\u20090.05). According to one-way ANOVA results, chronic exposure to early or adult life adversity decreased body weight (P\u2009<\u20090.0001), Catalase activity and GSH levels (P\u2009<\u20090.0001) and increased malondialdehyde level (P\u2009=\u20090.0006) in plasma. Pancreatic MDA and IL-1β contents elevated just in MS-CSDS rats (P\u2009<\u20090.05). Maternal separation shapes vulnerability to develop corticosterone hypersecretion, insulin resistance, pancreatic oxidative, and inflammatory damages associated with chronic exposure to later social challenges, which could potentially trigger metabolic disorders.