Pang, K. | bioRxiv Science

bioRxiv2019

An high dose of a conjugated linoleic acid increases fatty liver and insulin resistance in lactating mice

This study aimed to evaluate the effect of a high dose of conjugated linoleic acid (CLA) on lactating mice. In experiment one, KUNMING mice were separated into four groups (n = 6 per group); the control (CON) group received 3.0% linoleic acid oil (LA), the L-CLA group received 1.0% LA and 2.0% CLA mixture, the M-CLA group received 2.0% LA and 1.0% CLA mixture, and the H-CLA group received 3.0% CLA mixture. Feeding proceeded from day 4 to day 10 during lactation. In experiment two, the CON group received 2.0% LA and the H-CLA group received 2.0% CLA. Blood parameters were analysed for all groups, and insulin tolerance tests (ITTs) were conducted. CLA treatment did not affect the dam weight, but it significantly decreased the food intake of dams. Furthermore, CLA decreased the weight of pups, which was attributed to lower milk fat. H-CLA group mice displayed increased liver weight and liver triglyceride content, as well as a higher TG content and {gamma}-GT activity in blood. Moreover, a high dose of CLA resulted in insulin resistance, possibly affecting the RBC and HCB of blood. In conclusion, lactating mice receiving a high dose of CLA led to fatty liver, insulin resistance, and impaired lactation performance.

physiology↗

bioRxiv2019

Anhedonia following mild traumatic brain injury in rats: A behavioral economic analysis of positive and negative reinforcement

Psychiatric disorders affect nearly 50% of individuals who have experienced a traumatic brain injury (TBI). Anhedonia is a major symptom of numerous psychiatric disorders and is a diagnostic criterion for depression. Recently, anhedonia has been divided into consummatory, motivational and decisional components, all of which may be affected differently in disease. Although anhedonia is typically assessed using positive reinforcement, the importance of stress in psychopathology suggests the study of negative reinforcement (removal or avoidance of aversive events) may be equally important. The present study investigated positive and negative reinforcement following a rat model of mild TBI (mTBI) using lateral fluid percussion. Hedonic value of and motivation for reinforcement was determined by behavioral economic analyses. Following mTBI, the hedonic value of avoiding foot shock was reduced. In contrast, the hedonic value of escaping foot shock or obtaining a sucrose pellet was not altered by mTBI. Moreover, neither motivation to avoid or escape foot shock nor motivation to acquire sucrose was modified by mTBI. Our results suggest that individuals experiencing mTBI may experience more stress because of poor proactive control of stress resulting from reduced hedonic value of avoiding aversive events.

animal behavior and cognition↗