Melatonin and Metformin Mitigate Doxorubicin-Induced Alveolar Bone Toxicity

Evidence concerning the osteotoxic effects of chemotherapy (doxorubicin) has been previously described. Periodontitis also progressively increases in patients receiving chemotherapy; however, the beneficial effects of melatonin and metformin on the alleviation of doxorubicin-induced osteotoxicity have never been investigated. Therefore, we investigated the negative impact of doxorubicin on alveolar bone homeostasis and the benefits of melatonin and metformin on the attenuation of doxorubicin-induced alveolar bone toxicity. Male Wistar rats were divided into 4 groups to receive either 1 mL of normal saline solution as a control group, 3 mg/kg of doxorubicin, 3 mg/kg of doxorubicin plus 10 mg/kg of melatonin, or 3 mg/kg of doxorubicin plus 250 mg/kg of metformin. Doxorubicin treatment was given on days 0, 4, 8, 15, 22, and 29, while interventions were given daily on days 0 to 29. Following euthanasia, blood and alveolar bones were collected for evaluation of oxidative stress, bone remodeling, inflammation, microarchitecture, and periodontal condition. We found that doxorubicin increased systemic oxidative stress, decreased antioxidative capacity, increased inflammation, decreased bone formation, increased bone reabsorption, impaired microarchitecture, and impaired periodontal condition of the alveolar bone. Although cotreatment with melatonin or metformin resulted in some improvement in these parameters, cotreatment with melatonin was more effective than cotreatment with metformin in terms of decreasing oxidative stress, reducing bone resorption, and improving microarchitecture and periodontal condition. All of these findings highlight the potential for antioxidants, especially melatonin, to ameliorate doxorubicin-induced alveolar bone toxicity.