Social isolation stress induces hepatic hypertrophy in C57BL/6J mice.

We previously reported that social isolation stimulated a stress response leading to increasing plasma corticosterone level and disruption of the hepatic lipid metabolism-related pathway, without changing body and organ weights, in mice after 4 weeks of social isolation stress, compared with the grouped-housing control (5 mice/cage). In this study, we evaluated the effects of social isolation stress for an extended period on physiologic changes in male C57BL/6J mice. Plasma corticosterone was reduced after 13 weeks, indicating mice might adapt to social isolation stress.

Effects of animal care procedures on plasma corticosterone levels in group-housed mice during the nocturnal active phase.

C57BL/6 mice were housed five per cage on a 12:12 h light/dark cycle. All animal care, including bed cleaning, was carried out during the nonactive phase. After 2 weeks, mean plasma corticosterone levels, collected during the nonactive (ZT6) and active (ZT18) phases, were 66.