Effect of orthodontic force on inflammatory periodontal tissue remodeling and expression of IL-6 and IL-8 in rats

Objective: To investigate effect of orthodontic force on inflammatory periodontal tissue remodeling and expression of IL-6 and IL-8 in rats. Methods: Eighty SD rats were randomly divided into 4 groups, blank control group (group A) with 5 rats, treatment normal group (group B) with 25 rats, inflammation control group (group (group C) with 25 rats, inflammation treatment group (group D) with 25 rats. Immunohistochemistry and histomorphometric analysis was performed to measure the expression of IL-6, IL-8 and the first molar to the recent movement in the distance. Results: The expression of IL-8 reached a maximum on day 5 and declined thereafter in group B; the expression of IL-6 reached a maximum on day 5 in group B. The expression of IL-6 and IL-8 was gradually weakened with time in group C. The expression of IL-6 and IL-8 were high, and reached a maximum on day 5 and declined thereafter in group D. AD of positive cells in group D were higher than group B at each time point (P<0.05). The time which 0.49 N orthodontic force was loaded was longer, orthodontic tooth movement distance was greater. Movement distance in group D were longer than group B (P<0.05). Conclusions: Orthodontic force as well as inflammatory stimulus can evoke the expression of IL-6 and IL-8. Under the combined effects of inflammation and orthodontic force, the expression of IL-6, IL-8 will increase.