Voluntary Wheel-Running by Ovariectomized Rats: Impacts on Weight Gain, Plasma Leptin and Insulin, Hindbrain Astrocytes and Toll-like Receptor 4

Weight gain, hormones, and neuroimmune factors in exercising OVX rats


  • Steven Rivera
  • Donald Wu
  • Randall Davis
  • Kathleen Curtis Oklahoma State University Center for Health Sciences College of Osteopathic Medicine (OSU-COM)


Although obesity is an ongoing healthcare challenge in the U.S., diet and exercise have limited efficacy in losing weight and maintaining the weight loss, particularly for post-menopausal women. Nonetheless, few preclinical studies focus on females, even though it is well-known that rats rapidly gain weight after ovariectomy. To evaluate the effect of exercise on weight gain, we gave one group of ovariectomized (OVX) rats access to running wheels for three weeks immediately after ovariectomy; a second group had access to running wheels that was delayed for three weeks after ovariectomy. We also investigated the effect of exercise on circulating metabolic hormones that communicate with the central nervous system (CNS), as well as on neuroimmune factors in CNS areas involved in the control of body weight. Body weight was assessed each week for six weeks, and circulating levels of metabolic hormones and central neuroimmune factors were assessed after six weeks. Regardless of whether exercise was initiated immediately or was delayed for three weeks, OVX rats gained weight at a slower rate during the first week of running. However, this transient effect was longer-lasting when running was delayed. Circulating insulin and leptin were decreased in OVX rats when running was delayed; hindbrain astrocyte activation and toll-like receptor 4 levels also were reduced. Thus, although adaptations to voluntary exercise may limit its efficacy as a weight loss strategy, even transient slowing of post-ovariectomy weight gain is associated with reductions in metabolic hormones, which may be related to region-specific modulation of central neuroimmune factors.






Biomedical Sciences