# Interrelationship Between Physical Exercise and Apical Periodontitis in Trained Rats

## TL;DR

This study found that physical exercise in rats does not affect the development of apical periodontitis, nor does the condition impact exercise capacity.

## Contribution

The study is the first to investigate the bidirectional relationship between physical exercise and apical periodontitis in trained rats.

## Key findings

- Physical exercise did not influence the development of apical periodontitis in trained rats.
- Apical periodontitis did not affect the physical exercise capacity of trained rats.
- No differences in bone resorption were observed between sedentary and exercised rats with apical periodontitis.

## Abstract

To assess the influence of physical exercise on apical periodontitis (AP) development, and the effect of AP on physical exercise capacity in exercise‐trained rats.

After animal Ethics Committee approval, 40 male Holtzman rats (9 weeks old) were distributed into the following four groups (n = 10/group): physical exercise without AP induction (Ex); physical exercise with AP induction (Ex‐AP); sedentary without AP induction (S); sedentary with AP induction (S‐AP). In trained groups, animals performed moderate‐intensity aerobic training (treadmill) for 11 weeks. The maximal capacity test (T
max) was performed at baseline (0 weeks), 8 and 11 weeks to analyse physical capacity and increase training velocity to maintain training intensity. In the AP‐induced groups, coronal access of the left maxillary and mandibular first and second molars was performed after 8 weeks of training, and the pulp chamber was kept open for 21 days. After euthanasia, the hemi‐mandible was submitted to histopathological, radiographical and micro‐computed tomography (micro‐CT) analyses to evaluate the inflammation, the area and the volume of periapical bone resorption, respectively.

The T
max results of trained groups were higher than those of sedentary groups (p < 0.05). There was no difference in T
max results between trained groups (Ex and Ex‐AP; p > 0.05), or between sedentary groups (S and S‐AP) (p > 0.05). Regarding volume and area of apical bone resorption, there was no difference between S‐AP and Ex‐AP (p > 0.05). Histopathological qualitative analysis also showed no differences between S‐AP and Ex‐AP.

Physical exercise did not influence AP development, nor did AP affect physical exercise capacity in trained rats.