Abstract: Objective To investigate the role of mammalian target of rapamycin (mTOR) in renal injury in rats with periodontitis. Methods Twenty male Wistar rats were randomly divided into control group and periodontitis group, with 10 rats in each group. The animal model of periodontitis group was established by 0.2 mm orthodontic wire ligation, and ligation was not conducted in the control group. After 8 weeks, gingival bleeding index, probing depth of periodontal pocket were, and loosening degree recorded and alveolar bone resorption was analyzed by Micro-CT. HE and PAS staining were used for histological analysis. qRT-PCR and Western Blot were used to detect the mRNA and protein expression of mTOR, phosphor-mTOR (p-mTOR) and BECN1 (Beclin-1) in kidney tissues of rats. Results Compared with the control group, the gingival tissue in periodontitis group showed obvious swelling, color, and texture changes, and the gingival bleeding index, the probing depth of periodontal pocket and the degree of loosening were significantly increased and alveolar bone resorption was obvious. The glomerular Bowman's capsular space was obviously dilated; basement membrane hyperplasia, renal tubule interstitial hyperemia was obvious, and brush margin was destroyed; there was no significant difference in renal function.The mRNA and protein expressions (p-mTOR/mTOR) of mTOR in periodontitis group were significantly higher than those in control group, and the mRNA and protein expressions of Beclin-1 were significantly lower than those in control group. Conclusion mTOR may play a role in periodontitis-related renal injury in rats by inhibiting autophagy.

Key words: periodontitis, renal injury, mammalian target of rapamycin