Voluntary Exercise Impacts Body Composition, Leptin and Vesicle Size in a Rat Model of Endometriosis

Abstract

Endometriosis is a chronic inflammatory condition caused by migration of endometrial tissue outside the uterine cavity resulting in dysmenorrhea, chronic pelvic pain and infertility. Current hormonal or surgical treatments for this debilitating condition are mostly focused towards infertility and pain relief. Physical activity has been shown to modulate body fat related factors, while having beneficial effects on chronic inflammatory conditions, and more recently on pain management.HypothesisExposure of animals with endometriosis to a voluntary exercise intervention will impact body composition and reduce vesicle development in an animal model of endometriosis.MethodsTissue from the uterine horn was sutured on the intestinal mesentery of female Sprague‐Dawley rats for endometriosis induction (day 0), while the Sham rats received sutures with no implants. Sham control rats (Sham; n=11) and an Endo group (Endo; n=11) were not exposed to exercise. Another Endo group (EEX; n=10) and Sham group (SHEX; n=10) had free access to running wheels after surgery until day of sacrifice (day 60). The Scurry Activity System software was used to collect the running wheel activity data (speed, distance and intensity). Weight change and food consumption were measured throughout the protocol. At sacrifice, vesicles were collected and measured, along with mesenteric fat, serum, and muscles.ResultsAll animals reached a minimum running distance of 2 km/day by day 7 after surgery. Regardless of endometriosis, there were no differences in average total distance ran per animal per group (318.48 ± 62.52 km in SHEX vs 471.22 ± 75.79 km in EEX) or average speed (2.23 ± 0.53 m/min in SHEX vs 3.08 ± 0.52 m/min EEX). Exposure to exercise significantly reduced the average weight of the vesicles (p<0.05) and average total area (p<0.01) when compared to the Endo no exercise group. Both groups exposed to running wheels consumed significantly more food after surgery when compared to the no exercise groups (p<0.001). The exercise rats gained significantly less weight throughout the protocol, although absolute weight at sacrifice was not significantly different across all groups. Endo animals had significantly higher amounts of mesenteric fat when compared to Sham (p<0.01), while exercise reversed this effect (p<0.001). Exercise significantly decreased leptin serum concentrations (p<0.001 vs Sham; p<0.05 vs Endo). The muscle/fat ratio was also increased in the exercised rats when compared to controls in gastrocnemius (p<0.05) and soleus (p<0.01).ConclusionsAccess to voluntary physical activity after endometriosis induction promotes decreased body fat composition and ameliorates the development of vesicles. The surgical induction of endometriosis did not impact ability to run. The role of leptin in endometriosis is still unclear, however modulation of its levels by exercise in this model highlights the need for further examination. Overall, our results suggest that exercise might be a beneficial tool that could be used by patients with endometriosis to help control their condition.Support or Funding InformationSupported in part by R15AT009915, R25GM082406, U54MD007579.