BACKGROUND: Motivation for the study. Apical periodontitis (AP) can trigger immune responses that affect other organs. Main findings. This animal study examined the effects of AP on renal tissue, finding significant changes in parameters such as renal corpuscle area and Bowman's space, which may have implications for chronic kidney disease. Implications. Future research will provide insight into how dental conditions may affect renal health. If confirmed, regular dental checkups would not only be critical to improve the overall health of patients with kidney disease, but could also serve as a preventive measure. OBJECTIVES.: To evaluate the effect of apical periodontitis (AP) induced in Wistar rats on histologically examined renal tissue. MATERIALS AND METHODS.: Fourteen 12-week-old male Wistar rats weighing an average of 250 grams were used. AP was induced with pulp exposure of the upper and lower first molars using a #1011 HL spherical bur in high rotation. The lesions were left exposed to the oral environment for a period of 7 weeks. Blood pressure was measured by the tail-cuff plethysmography method from the fourth week. The kidney was dissected for histological analysis (H&E). Mann-Whitney and Student's t-test were used for non-parametric and parametric data, respectively, with a significance level of 5%. RESULTS.: A statistically significant increase in both Bowman's space area and renal corpuscle area was found in the AP group (p<
0.05). The AP group had a higher percentage of renal tissue with inflammatory infiltrate, but without significant difference. Blood pressure did change during the experimental period and no difference was identified between the groups. CONCLUSIONS.: Induction of AP in Wistar rats resulted in significant changes of certain renal histological parameters, suggesting a possible interaction between AP and renal tissue that requires further research.