OBJECTIVE To observe the intervention effect of puerarin on the rats with bacterial periodontitis by regulating nucleotide-binding oligomeric domain-like receptor protein 3/Caspase-1 (NLRP3/Caspase-1) signaling pathways.

METHODS Totally 44 male SPF rats were chosen as subjects and were divided into the blank group, the model group, the puerarin group and the puerarin plus inhibitor group. The models of rats with bacterial periodontitis were successfully established. The periodontal indexes and alveolar resorption were observed and compared among the groups.

RESULTS The sulcus bleeding index (SBI) and plaque index (PLI) scores of the model group and the puerarin plus inhibitor group were higher than those of the blank group; the NLRP3 level was 0.87±0.09 in the model group, 0.85±0.08 in the puerarin plus inhibitor group, higher than 0.18±0.03 in the blank group; the Caspase-1 level was 1.15±0.11 in the model group, 1.03±0.10 in the puerarin plus inhibitor group, higher than 0.35±0.04 in the blank group. The trabecular separation spacing (Tb. Sp), cemento-enamel junction-facial bone crest (CEJ-FBC), interleukin--1β(IL-1β) level, interleukin-6 (IL-6) level, tumor necrosis factor-α(TNF-α)level and osteoclast counts of the model group and the puerarin plus inhibitor group were higher than those of the blank group; while the trabecular thickness (Tb. Th), bone volume/tissue volume (BV/TV) and bone mineral density (BMD) of the model group and the puerarin plus inhibitor group were lower than those of the blank group. The SBI and PLI scores of the puerarin group were lower than those of the model group; the NLRP3 level of the puerarin group was 0.20±0.04, lower than 0.87±0.09 of the model group; the Caspase-1 level of the puerarin group was 0.37±0.05, lower than 1.15±0.11 of the model group. The Tb. Sp, CEJ-FBC, IL-1βlevel, IL-6 level, TNF-α level and osteoclast counts of the puerarin group were lower than those of the model group; while the Tb. Th, V/V and BMD of the puerarin group were higher than those of the model group. The SBI and PLI score of the puerarin plus inhibitor group were higher than those of the puerarin group; the NLRP3 level of the puerarin plus inhibitor group was 0.85±0.08, higher than 0.20±0.04 of the puerarin group; the Caspase-1 level of the puerarin plus inhibitor group was 1.03±0.10, higher than 0.37±0.05 of the puerarin group. The Tb. Sp, CEJ-FBC, IL-1β level, IL-6 level, TNF-α level and osteoclast counts of the puerarin plus inhibitor group were higher than those of the puerarin group, while the Tb. Th, V/V and BMD of the puerarin plus inhibitor group were lower than those of the puerarin group, there were significant differences in the above comparisons (P<0.05).

CONCLUSIONS Puerarin can effectively reduce the periodontal plaque index and bleeding index of the rats with bacterial, reduce the levels of inflammatory factors and alleviate the damage of tissue. The action mechanisms may be associated with the NLRP3/Caspase-1 signaling pathways.