Sex differences in response to activity-based anorexia model in C57Bl/6 mice
Résumé
Anorexia nervosa is a severe eating disorder often associated with physical hyperactivity and is more frequently observed in female sex. Activity-Based Anorexia (ABA) model combines physical activity (PA) and reduced food intake and thus allows a better understanding of the mechanisms underlying anorexia nervosa. We aimed to assess sex differences in response to ABA model in C57Bl/6 mice. Twenty four male and 16 female C57BL/6 mice were studied. ABA mice were placed in individual cages with a continuously recorded activity wheel. ABA mice had a progressive limited food access from 6 h/day (day 6) to 3 h/day (day 9) until the end of the protocol (day 17). Body weight and food intake were daily measured. We studied physical activity during 24 h, during the dark phase (D-PA) and the light phase (L-PA). We also evaluated the feeding anticipatory physical activity (A-PA), the physical activity during food intake period (FI-PA) and the post-prandial physical activity (PP-PA). We observed 16.7% of mortality in males (4 out of 24 mice) during ABA protocol while no female mice died (p = 0.09). At day 17, food intake was significantly higher in females than in males (p < 0.05) that was associated with a lower body weight loss than in females (p < 0.05). Before limited food access, no gender differences in wheel running activity were observed. From day 9, A-PA significantly increased over time in males (p < 0.05 vs females) while females exhibited higher FI-PA and PP-PA (p < 0.05 vs males). Correlations between wheel running activities and, respectively, food intake and body weight loss showed gender differences, in particularly for L-PA and A-PA. Our results suggest a greater susceptibility of male mice to develop ABA, males and females exhibit different patterns of physical activity after limitation of food access. Underlying mechanisms should be further investigated.