Abstract
Treatments for endometriosis include pharmacological or surgical procedures that produce significant side effects. We aimed to determine how environmental enrichment (EE) could impact the progression of endometriosis using the autotransplantation rat model. Female rats were exposed to EE (endo-EE: toys and nesting materials, 4 rats per cage, larger area enclosure) or no enrichment (endo-NE: 2 rats per cage) starting on postnatal day 21. After 8 weeks, sham surgery or surgical endometriosis was induced by suturing uterine horn tissue next to the intestinal mesentery, then allowed to progress for 60 days during which EE or NE continued. At the time of killing, we measured anxiety behaviors, collected endometriotic vesicles and uterus, and processed for quantitative real-time polymerase chain reaction for corticotropin-releasing hormone (CRH), urocortin-1, CRH receptors type 1 and type 2, and glucocorticoid receptor (GR). Endometriosis did not affect anxiety-like behaviors, yet rats in enriched conditions showed lower basal anxiety behaviors than the nonenriched group. Importantly, the endo-EE group showed a 28% reduction in the number of endometriosis vesicles and the vesicles were significantly smaller compared to the endo-NE group. Endometriosis increased CRH and GR only in the vesicles of endo-NE, and this increase was dampened in the endo-EE. However, urocortin 1 was increased in the vesicles of the endo-EE group, suggesting different pathways of activation of CRH receptors in this group. Our results suggest that the use of multimodal complementary therapies that reduce stress in endometriosis could be an effective and safe treatment alternative, with minimal side effects.