Objective:To investigate the effects of experimental periodontitis on serum C reactive protein(CRP) and insulin resistance in obese rats.Methods:4 week old SD rats (n=35)were fed with high fat diet for 16 weeks to establish the model of obesity.According to the obesity criteria,5 rats were screened out.According to the proportion of 1:2,10 rats were randomly selected as obese control group,20 obese rats were used for the establishment of the obesity with periodontitis model(combination group) by periodontal ligation using silk thread.4 rats died after ligation.Before periodontal ligation,1 and 4 weeks after periodontal ligation,orbital venous blood were collected for the detection of fasting blood glucose and fasting insulin.Homeostasis model assessments of insulin resistance index(HOMA-IR) and beta cell function index(HOMA-β) were calculated.The level of serum CRP was examined by ELISA.Results:The level of CRP in the combination group was increased 1 week after periodontal ligation,and then gradually decreased in the following 4 weeks(F=7.773,P=0.004).HOMA-IR in the combination group were higher than that in the obese group(F=-4.691,P=0.000),and beta cell function index was significantly lower(F=3.672,P=0.002) than that in the control group 4 weeks after periodontal ligation.Conclusion:The experimental periodontitis may affect the serum level of CRP in obese rats,aggravate insulin resistance and decrease the function of beta cells in obese rats.

Objective To explore the mechanism of the experimental periodontitis and initial periodontal therapy on insulin resistance of obese rats associated with periodontitis.Methods Blood samples were collected from SD rats of obese group,periodontitis associated with obese group,periodontal therapy group and control group.Body index,data about insulin resistance and Observed pathological changes were calculated.Results Comparison of four groups:more severe insulin resistance and islet structural dysfunction was observed in obesity with periodontitis group than that of group with obesity alone.After periodontal therapy,inflammation and insulin resistance may be improved.Results from pathological specimens also supported this result.Conclusions The periodontitis with obesity can enhance the inflammatory state of obesity and cause the deterioration of insulin resistance.The initial periodontal treatment can relieve the inflammation of obesity with periodontitis and improve the resistance of insulin.It may be the reason of insulin resistance when obesity with periodontitis that the signaling pathways of IRS-1 and IRS-2 blocked,and PDX-1,GK,GLUT and other protein expression inhibited.

Objective To investigate the effect of emodin on insulin resistance and serum inflammatory factors in obese rats. Methods 16 obese rats with experimental periodontitis were selected and then randomly di-vided into periodontal treatment group(control group)and periodontal therapy combined with emodin group(medi-cation group). All the rats were sacrificed 2 weeks after treatment. Before the rats were killed,the orbital vein blood was taken to detect fasting blood glucose,fasting insulin;levels of serum C-reactive protein(CRP)and tu-mor necrosis factor-α(TNF-α)were detected by enzyme linked immunosorbent assay.Results 2 weeks after peri-odontal treatment,level of CRP was significantly lower in the medication group than in the control group(t =2.170,P = 0.044);TNF-α was significantly lower in the medication group than in the control group(t = 3.074, P=0.007).Fasting blood glucose level was lower in the medication group than in the control group,and HOMA-β was higher than the control group,no statistical differences were found between the two groups.Conclusions Non-surgical periodontal treatment combined with local administration of emodin can help repair of periodontal epitheli-al barrier and reduce levels of serum inflammatory factors.