Fig. 1

Experimental protocol for intermittent PTH administration and changes in body weights and fasting glucose levels during the experimental period. Rats were divided into five groups: C, P, P + PTH, DP, and DP + PTH. a Experimental protocol: on 1 week after induction of diabetes by STZ, periodontitis was induced by placing bilateral ligatures around the mandibular first molars using dental floss. After placement of the ligatures, the DP and DP + PTH groups were given intraperitoneal injections of calcein (10 mg/kg) on days 10 and 27, and alizarin red (20 mg/kg) on day 20, respectively. During 30 days after the induction of periodontitis, the P + PTH and DP + PTH groups were subcutaneously administered PTH three times per week (40 μg/kg). On days 0 and 30, PTH was administered 4 h before both placement of the ligatures and the time of sacrifice, respectively. b Body weights in each group and c Fasting glucose levels in each group. Data are presented as the mean ± SE. *P < 0.05 compared with the C group