Beneficial Effects of Voluntary Wheel Running in an Endometriosis Animal Model
Authors: Cruz Myrella L , Chompre Gladys , Velazquez Johnathan , Rivera‐Mendez Raquel M , Appleyard Caroline B 
Published: June 2021

Endometriosis is a chronic gynecological disorder defined as the presence of endometrial glands and stroma outside the endometrial cavity. This condition is characterized by peritoneal inflammation, fibrosis, adhesions and ovarian cysts, which result in chronic pelvic pain, painful periods and infertility. Our previous studies have demonstrated that exposure to stress and modulation of the hypothalamic pituitary axis exacerbates the development and severity of endometriosis. A physically active lifestyle has been shown to confer health benefits in many chronic conditions by potentially acting as a stress buffer. However, no experimental data exist regarding the impact of exercise on the course of endometriosis.HypothesisPhysical exercise can ‘realign/reset’ dysregulation of the brain‐gut axis resulting in reduced endometriosis symptoms in an animal model.MethodsEndometriosis was induced in female Sprague Dawley rats by implanting uterine tissue next to the intestinal mesentery on day 0. Sham controls received sutures only. One group of endometriosis animals had access to a running wheel for 2 weeks prior to endometriosis induction until time of sacrifice at day 60 (EEX; n=6). Sham controls (Sham; n=5) and Endo (n=6) received no exercise. Anxiety was measured using open field and zero maze 1 week after surgery and at time of sacrifice. All animals were examined for developed vesicles which were collected and measured. Colon and uterine tissue were analyzed for damage and myeloperoxidase (MPO) levels. Brain, liver, spleen, adrenal glands, leg muscles and fat were collected and stored for future analysis.ResultsEndo animals developed vesicles in 82.61% of the implants with an average total area of 50.27±9.48mm2 and weight of 0.053±0.006g per animal. These animals also had significantly increased macroscopic colonic damage compared to Sham (p<0.0001). Exposure to exercise significantly decreased the number of vesicles that developed (54.17%; p<0.05), as well as their size (20.25±5.84mm2, p<0.05) and weight (0.035±0.005g, p<0.05), although no significant differences in anxiety were noted between the groups. EEX also had less macroscopic (p<0.05) and microscopic colonic damage, with no significant difference in MPO. EEX had higher levels of lactoferrin, known to be a natural immunomodulator, which tended to inversely correlate with lesion size. Adrenal glands tended to be smaller in Endo compared to Sham, whereas EEX had significantly larger adrenal glands/body weight than Endo alone (p<0.05).ConclusionsOur results suggest that voluntary physical activity might protect against endometriosis and alleviate the associated symptomatology via immune modulation of the brain‐gut axis. This offers the potential for further exploration of this complementary therapy in the patient population.Support or Funding InformationSupported in part by P20GM103475‐16 & R15AT009915This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.