[Influence of periodontal non-surgical therapy on serum interleukin 6 expression and carotid artery wall in rats with periodontitis and type 2 diabetes mellitus].

Objective: To study the effect of periodontal non-surgical treatment on serum interleukin-6 (IL-6) expression and carotid vascular wall in a rat model of chronic periodontitis (CP) with type 2 diabetes mellitus (T2DM).

Methods: Twenty-eight 6-week-old SD rats were randomly divided into group A (control group, 7 rats) and group B (T2DM+CP group, 21 rats). According to different intervention measures, group B was randomly subdivided into B1 (natural process), B2 (periodontal mechanical treatment), and B3 (periodontal mechanical treatment + 2% minocycline hydrochloride + systemic metronidazole plus amoxicillin). Serum IL-6 was measured by enzyme-linked immunosorbent assay, and carotid tissue was observed under light microscopy after hematoxylin-eosin (HE) staining.

Results: The carotid artery wall of group A was normal. In group B1, the endothelial cells disappeared, the elastic fibers of the middle membrane were disordered, the local necrosis of smooth muscle tissue was amorphous particles, a small amount of calcium salt was deposited, and the wall thickening was obvious. The endothelial cells in groups B2 and B3 disappeared, and the smooth muscle cells in the middle membrane underwent denaturation. No significant thickening of the vessel wall was noted. The serum IL-6 level in group B1 continually increased with time, and it was higher than that in group A (P<0.001). The IL-6 levels of groups B2 and B3 peaked a week after the first intervention. Subsequently, IL-6 levels gradually decreased. At the last point (five weeks after the second intervention ), the IL-6 levels of groups B2 and B3 were significantly lower than that of group B1 (P<0.001).

Conclusions: For rats with periodontitis and diabetes, periodontal mechanical treatment may elevate serum IL-6 levels in the short term but might reduce the whole inflammatory state in the long term. Thus, this treatment might be valuable to the improvement of vascular disease. The adjunctive benefits of systemic metronidazole and amoxicillin in non-surgical periodontal therapy are decreased serum IL-6 expression and normal carotid artery.