Serum levels of estrogen decrease at climacterium and directly interfere with the urogenital tract. Urinary bladder (UB) is responsive to hormonal changes, especially estrogen. Resistance exercise elicits benefits on severe chronic diseases. Nevertheless, it is still unclear whether the resistance exercise directly affects the UB in ovariectomized (OVx) rats. This study focused on investigating the effects of resistance exercise on UB function and morphology in OVx and control rats. Adult female Wistar rats (∼250-300 g, 14-16 weeks old) [control (n = 20) and OVx (n = 20)] were divided in the following groups: sedentary (SED), and trained over 1 week (acute), 3 weeks (intermediate), and 10 weeks (chronic). Training was carried out in a ladder, with six bouts in alternate days with 75% of body weight load attached to the tail of the animal. Afterward, the animals were isoflurane anesthetized for evaluation of intravesical pressure (IP) changes upon topical administration of acetylcholine (Ach) and noradrenaline (NE) on the UB. At the end of the experiment, the UB was harvested for histological analysis and stained with hematoxylin-eosin and picrosirius red. Ach increased the IP in both OVx and control rats, whereas NE decreased the IP. However, the acute and intermediate groups showed attenuated responses to Ach and NE, while the chronic groups recovered the responses to Ach and NE close to those observed in SED groups. Acute and intermediate groups also showed decreased thickness of the muscular layer, with a reversal of the process with chronic training. In the OVx groups, the acute training reduced the thickness of the smooth muscle and mucosal layers, whereas chronic training increased it. Urothelium thickness decreased in the OVx SED and acute groups. Collagen type I fibers (CI-F) reduced in OVx SED acute and intermediate groups, while collagen type III fibers (CIII-F) increased in the OVx acute group. In the mucosal layer, the volume density of CFs reduced in OVx rats compared to control groups and chronic training resulted in their recovery. Our data suggest that chronic resistance exercise for 10 weeks reversed the functional and morphological changes caused by hypoestrogenism.

Objective: investigate whether resistance exercise can induce morphological and functional alterations in urinary bladder (UB) in multiparous rats. Methods: we used 40 adults female Wistar rats of which 20 were nulliparous and 20 were multiparous submitted to different volumes of moderate resistance exercise (one, three or ten weeks). Animals were submitted to the functional evaluation of UB. At the end of the protocol, the UB was removed, weighed and stained with hematoxylin and eosin for structural evaluation, and picrosirius red for collagen fibers. Results: we observed that multiparity promoted increase in body mass, reduction in UB layers, decrease in volume densities of collagen fibers I and III. However, 10-weeks of training was able to reverse the negative effects of multiparity. Conclusion: the intervention of physical exercise in 10 weeks times seems to cause greater benefit in UB of multiparous animals by preventing morphofunctional changes that trigger lower urinary tract symptoms, such as urinary loss.