Doxycycline (DOX) exhibits anti-inflammatory and MMP inhibitory properties. The objectives of this study were to evaluate the effects of DOX on alveolar bone repair. Controls (CTL) and DOX-treated (10 and 25 mg. kg? 1) molars were extracted, and rats were killed 7 or 14 days later. The maxillae were processed and subjected to histological and immunohistochemical assays. Hematoxylin-eosin staining (7th day) revealed inflammation in the CTL group that was partly reversed after DOX treatment. On the 14th day, the CTL group exhibited bone neoformation, conjunctive tissue, re-epithelization and the absence of inflammatory infiltrate. DOX-treated groups exhibited complete re-epithelization, tissue remodelling and almost no inflammation. Picrosirius red staining in the DOX10 group (7th and 14th days) revealed an increased percentage of type I and III collagen fibres compared with the CTL and DOX25 groups. The DOX10 and DOX25 groups exhibited increases in osteoblasts on the 7th and 14th days. However, there were fewer osteoclasts in the DOX10 and DOX25 groups on the 7th and 14th days. Wnt-10bimmunopositive cells increased by 130% and 150% on the 7th and 14th days, respectively, in DOX-treated groups compared with the CTL group. On the 7th day, Dickkopf (Dkk)-1 immunostaining was decreased by 63% and 46% in the DOX10 and DOX25 groups, respectively. On the 14th day, 69% and 42% decreases in immunopositive cells were observed in the DOX10 and DOX25 groups, respectively, compared with the CTL group. By increasing osteoblasts, decreasing osteoclasts, activating Wnt 10b and neutralising Dkk, DOX is a potential candidate for bone repair in periodontal diseases.

Background/Aims: Therapies aimed at modulating cytokines have been used to treat inflammatory illnesses, such as inflammatory bowel disease. On the other hand, patients may become intolerant, refractory, or present with several side effects. Arthrospira (Spirulina) platensis (SPI) is a blue-green microalga with bioactive molecules that have been evaluated to treat inflammatory diseases. On the other hand, few studies have examined their effects on the production of specific cytokines and the intestinal architecture in dextran sulfate sodium (DSS)-induced colitis. Therefore, this study examined the effects of a treatment using SPI in a murine model of intestinal inflammation. Methods: All mice (C57BL/6 male) were evaluated daily for their food and water intake, bodyweight variations, and clinical signs of disease. Colon inflammation was induced by exposure to DSS for 6 consecutive days. SPI was given orally at 50, 100, and 250 mg/kg/day. ELISA was performed to assess the production of cytokines. Myeloperoxidase and nitric oxide were also investigated. The level of microscopic damage was assessed by staining colon sections with hematoxylin and eosin. Results: SPI attenuated the DSS-induced inflammation, with improvements in the clinical signs and a decrease in the production of inflammatory cytokines, such as tumor necrosis factor-α and interferon-γ. In addition, particularly at 250 mg/kg, SPI attenuated the severity of colitis by modulating the level of mucosal and submucosal cell infiltration, which preserved the epithelial barrier. Conclusions SPI may be an alternative source of bioactive molecules with immunomodulatory properties, and has great potential to be used in the treatment of inflammatory diseases.