Abstract Inducible nitric oxide synthase (iNOS) is one of the enzymes responsible for the synthesis of nitric oxide (NO), which is an important signaling molecule with effects on blood vessels, leukocytes, and bone cells. However, the role of iNOS in alveolar bone healing remains unclear. This study investigated the role of iNOS in alveolar bone healing after tooth extraction in mice. Methodology C57Bl/6 wild type (WT) and iNOS genetically deficient (iNOS-KO) mice were subjected to upper incision tooth extraction, and alveolar bone healing was evaluated by micro-computed tomography (μCT) and histological/histomorphometric, birefringence, and molecular methods. Results The expression of iNOS had very low control conditions, whereas a significant increase is observed in healing sites of WT mice, where iNOS mRNA levels peak at 7d time point, followed by a relative decrease at 14d and 21d. Regarding bone healing, both WT and iNOS-KO groups showed the usual phases characterized by the presence of clots, granulation tissue development along the inflammatory cell infiltration, angiogenesis, proliferation of fibroblasts and extracellular matrix synthesis, bone neoformation, and remodeling. The overall micro-computed tomography and histomorphometric and birefringence analyses showed similar bone healing readouts when WT and iNOS-KO strains are compared. Likewise, Real-Time PCR array analysis shows an overall similar gene expression pattern (including bone formation, bone resorption, and inflammatory and immunological markers) in healing sites of WT and iNOS-KO mice. Moreover, molecular analysis shows that nNOS and eNOS were significantly upregulated in the iNOS-KO group, suggesting that other NOS isoforms could compensate the absence of iNOS. Conclusion The absence of iNOS does not result in a significant modulation of bone healing readouts in iNOS-KO mice. The upregulation of nNOS and eNOS may compensate iNOS absence, explaining the similar bone healing outcome in WT and iNOS-KO strains.

ABSTRACT BACKGROUND: Elderly men have been characterized as a group vulnerable to suicide, motivated by loneliness, loss of loved ones and feelings of uselessness to family members. OBJECTIVES: To ascertain the prevalence of different mental disorders among elderly men who attempted suicide. DESIGN AND SETTING: Systematic review of observational studies developed as a result of a partnership between two postgraduate schools (Lagarto and Uberlândia). METHODS: An electronic search was performed in eight electronic databases, including “grey literature”, in January 2019. Observational studies that assessed mental disorders among men older than 60 years who attempted suicide were eligible for inclusion. RESULTS: Among the disorders evaluated, mood disorders had the highest prevalence (42.0%; 95% confidence interval, CI: 31.0-74.0%; I2: 0.0%; P = 0.763), followed by substance use-related disorders (41.0%; 95% CI: 8.0-74.0%; I2: 96.4; P < 0.001) and, lastly, schizophrenic disorders (5.0%; 95% CI: 0.0%-14.0%; I2: 80.3%; P = 0.024). CONCLUSIONS: It seems that mood disorders and substance use-related disorders are quite prevalent among elderly men with mental disorders who attempted suicide. It is important to consider the role of healthcare services in making early diagnoses of mental disorders among elderly men, in order to diminish the chances of suicide attempts among them. SYSTEMATIC REVIEW REGISTRATION: CRD42018105981.