RESUMO
Objectives@#To establish SD rat model with type 2 diabetes mellitus (DM) and concomitant chronic periodontitis (CP) and to evaluate the influence of periodontitis on the vascular lesions of type 2 diabetes rats.@*Methods@#Totally 241 clean level SD rats were randomly divided into four groups, group A (normal control, NC, n=27), group B (DM, n=34), group C (CP, n=90) and group D (DM+CP, n=90). The rats of DM group were fed with high-fat and high-sugar diet for 8 to 10 weeks, and then were multiply injected with small dose streptozotocin under the condition of ice bath. Blood sugar levels after the injection were dynamically monitored at 72 h, 1 week, 2 weeks and 4 weeks, respectively. The CP model was established by means of ligation. Bilateral maxillary first and second molars were selected and ligated using 0.2 mm orthodontic wires binding with 4-0 surgical suture soaked with Porphyromonas gingivalis (Pg) suspension. After a period of 14 weeks, all the rats were put to death. Maxillary samples were subjected to methylene blue staining to observe alveolar bone loss. Bilateral carotid artery specimens were collected. The left carotid artery specimens were used to detect the prevalence of Pg using quantitative real-time PCR. The right carotid artery specimens were used to observe pathological changes.@*Results@#Blood sugar levels of rats in group B and D increased and changed sharply after Streptozotocin injection with in 1 week. Symptoms of 'more drink, more food and body weight loss’ appeared. The fasting blood glucose (FBG) was more than 7.8 mmol/L and (or) the random blood glucose (RBG) was more than 17.8 mmol/L. Both FBG and RBG became stable after 2 to 3 weeks. Levels of HbA1C in group B and D ([7.32±0.45]%, [9.41±0.45]%) were significantly higher than that of group A ([4.02±0.45]%) (P<0.01). Rats of group D were observed the most severe bone loss showing wider interdental space and furcation involvement. Pathological results of carotid artery tissues of group D showed the worst lesions including thinning and calcification of vessel walls, and breaking down or disappearance of elastic fibers. The prevalences of DNA of Pg in groups of A, B, C and D were 3/7, 3/7, 6/7 and 7/7, respectively. The bacteria numbers detected by quantitative real-time PCR in groups C and D were significantly higher than that of groups A and B (P<0.01).@*Conclusions@#Rat model of type 2 DM with periodontitis was successfully established in the present study. Carotid artery specimens from DM+CP model rats showed typical vascular lesions such as calcification and fiber disorders. Pg was found in all carotid specimens and the highest bacteria numbers were detected in the composite model rats. The Pg might play a role in the progress of diabetes vascular lesions.
RESUMO
<p><b>OBJECTIVE</b>To investigate the effect of tooth extraction with antibiotics on atherosclerosis, and to examine the expression of serum interleukin 6(IL-6) and the pathological changes of the carotid artery in chronic periodontitis(CP) rats with or without atherosclerosis(As).</p><p><b>METHODS</b>A total of 44 SD rats were randomly divided into four groups, group A(normal control), group B(As), group C(CP), group D(CP+As). After model establishment, group C and group D were randomly divided into group C1/D1 (tooth extraction) and group C2/D2(tooth extraction with antibiotics) according to random number table and received the corresponding oral intervention treatment respectively. Serum IL-6 levels were determined by enzyme linked immunosorbent assay(ELISA) respectively one week before the intervention, one week after the first intervention, one, three, five weeks after the second intervention. The pathological changes of the carotid artery were accessed under light microscope.</p><p><b>RESULTS</b>At all sampling time points, the levels of serum IL-6 in group B, C, D were higher than that of group A, with group D1 being increased most obviously, significantly higher than that of group A(P< 0.001). One week after the second intervention, the content of IL-6 in group C and group D peaked[C1(127.0 ± 29.9) ng/L, C2: (120.6 ± 23.1) ng/L, D1: (175.1 ± 50.8) ng/L, D2: (160.5 ± 37.7) ng/L], and was significantly higher than that of group B[B: (43.4 ± 7.5) ng/L,P<0.001]. Then they all had varying degrees of decline, 5 weeks after the second intervention, group C1 and D1 were still higher than that of group B, but group C2 and D2 were lower than that of group B. At all sampling time points, the levels of serum IL- 6 in group C2/D2 were lower than those in group C1/D1, 5 weeks after the second intervention the difference was most obvious and statistically significant(P<0.001). Pathology showed that the carotid artery wall in group A was normal. The carotid artery wall was thickened in group B, inflammatory cells and foam cells could be seen, and elastic fibers disordered. The carotid artery wall in group C1 was uneven, foam cells and a small amount of inflammatory cells were visible, and elastic fiber disordered. Obvious thickening was not seen in the carotid artery wall of group C2, a small amount of foam cells and inflammatory cells were found, and elastic fiber mildly disordered. The carotid artery wall in group D1 was obviously uneven, calcium salt deposits were visible in the artery wall, a large amount of inflammatory cells and foam cells could be found, and elastic fiber disordered. Obvious thickening was not seen in the carotid artery wall of group D2, a small amount of inflammatory cells and a large amount of foam cells could be seen, and elastic fiber disordered.</p><p><b>CONCLUSIONS</b>Periodontitis and hyperlipidemia could increase the level of serum IL- 6 and the risk of the As. In chronic periodontitis rats with or without atherosclerosis, when periodontal inflammation was not controlled, tooth extraction may increase the risk of the As. At the time of tooth extraction, giving the anti-inflammatory treatment can reduce the risk to a certain extent.</p>
