Imbalance of oxidative/anti-oxidative status induced by periodontitis is involved in apoptosis of rat submandibular glands

Objective: Epidemiologic studies suggest a relationship between periodontitis and salivary gland dysfunction. A rat periodontitis model was used to investigate whether a causal relationship exists between periodontitis and pathological changes of submandibular glands. Design: Fourteen male Wistar rats (8 weeks old) were divided into two groups (n = 7/group): a control group and periodontitis group. Periodontitis was induced by ligature placement around the mandibular first molars. Serum levels for reactive oxygen metabolites, anti-oxidant and tumour necrosis factor (TNF)-α were measured at baseline, 2 and 4 weeks. At 4 weeks, the levels of 8-hydroxydeoxyguanosine were determined to evaluate oxidative damage of submandibular glands. Expression of TNF-α mRNA and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) as well as histological findings were also evaluated in the submandibular glands. Results: The rats with experimental periodontitis showed increase in the levels of serum reactive oxygen metabolites and TNF-α, and a decrease of anti-oxidant power in a time-dependent manner. At 4 weeks, these rats also had significantly increased levels of 8-hydroxydeoxyguanosine and TNF-α, and increased number of TUNEL-positive cells and vacuolisation in the submandibular glands compared to the control rats. Conclusions: Imbalance of circulating oxidative/anti-oxidative status may be involved in vacuolisation and apoptosis of submandibular glands in the rat periodontitis model.