Didem Dagdeviren1, Zana Kalajzic2, Douglas J Adams3, Ivo Kalajzic4, Alan Lurie1, Maija I Mednieks5, Arthur R Hand6. 1. Division of Oral and Maxillofacial Radiology, School of Dental Medicine, USA. 2. Department of Craniofacial Sciences, School of Dental Medicine, USA. 3. Department of Orthopaedic Surgery, School of Medicine, USA. 4. Department of Reconstructive Sciences, School of Dental Medicine, USA. 5. Department of Oral Health and Diagnostic Sciences, School of Dental Medicine, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030, USA. 6. Department of Craniofacial Sciences, School of Dental Medicine, USA. Electronic address: hand@uchc.edu.
Abstract
OBJECTIVE: To determine if spaceflight and microgravity affect non-weight bearing bones and development and mineralization of teeth, reasoning that combining an organ and a cellular level approach can lead to greater insights about these effects. DESIGN: Mandibles and incisors of mice flown on the US STS-135 space shuttle mission and the Russian Bion-M1 satellite were studied using micro-computed tomography and immunohistochemistry. Ground controls were mice housed in standard vivarium cages and flight habitats. RESULTS: Incisor length was greater in the 13-day STS-135 flight mice than in either control group. Initial incisor mineralization occurred more posteriorly, and incisor, enamel and dentin volumes and enamel and dentin thicknesses were greater in the 30-day Bion-M1 flight and habitat control mice than in vivarium control mice. Mandibular bone volume (BV) was increased in STS-135 flight and habitat groups and decreased in Bion-M1 flight and habitat groups compared to vivarium controls. No significant histological alterations occurred, but changes were seen in the bone and tooth proteins dentin sialoprotein, amelogenin and the type II regulatory subunit of protein kinase A. The percentage of sclerostin positive osteocytes was greatest in flight mice, and greater in STS-135 flight and habitat control mice than in the corresponding Bion-M1 groups. TRAP staining, representing osteoclastic bone remodeling, differed between the two flights and corresponded with changes in BV. Interpretation of the findings was limited by a small number of flight mice, different sex and ages of the mice in the two missions, and different habitats and diets. CONCLUSIONS: Microgravity has measurable effects on mandibular bone physiology and incisor development and mineralization. The results also showed that the habitat had an effect either in flight or ground control samples, as demonstrated by the changes in BV and apparent slowing of incisor eruption. Therefore, developing appropriate habitats is critical for future spaceflight missions.
OBJECTIVE: To determine if spaceflight and microgravity affect non-weight bearing bones and development and mineralization of teeth, reasoning that combining an organ and a cellular level approach can lead to greater insights about these effects. DESIGN: Mandibles and incisors of mice flown on the US STS-135 space shuttle mission and the Russian Bion-M1 satellite were studied using micro-computed tomography and immunohistochemistry. Ground controls were mice housed in standard vivarium cages and flight habitats. RESULTS: Incisor length was greater in the 13-day STS-135 flight mice than in either control group. Initial incisor mineralization occurred more posteriorly, and incisor, enamel and dentin volumes and enamel and dentin thicknesses were greater in the 30-day Bion-M1 flight and habitat control mice than in vivarium control mice. Mandibular bone volume (BV) was increased in STS-135 flight and habitat groups and decreased in Bion-M1 flight and habitat groups compared to vivarium controls. No significant histological alterations occurred, but changes were seen in the bone and tooth proteins dentin sialoprotein, amelogenin and the type II regulatory subunit of protein kinase A. The percentage of sclerostin positive osteocytes was greatest in flight mice, and greater in STS-135 flight and habitat control mice than in the corresponding Bion-M1 groups. TRAP staining, representing osteoclastic bone remodeling, differed between the two flights and corresponded with changes in BV. Interpretation of the findings was limited by a small number of flight mice, different sex and ages of the mice in the two missions, and different habitats and diets. CONCLUSIONS: Microgravity has measurable effects on mandibular bone physiology and incisor development and mineralization. The results also showed that the habitat had an effect either in flight or ground control samples, as demonstrated by the changes in BV and apparent slowing of incisor eruption. Therefore, developing appropriate habitats is critical for future spaceflight missions.
Authors: Alix C Deymier; Andrea G Schwartz; Chanteak Lim; Brian Wingender; Akhilesh Kotiya; Hua Shen; Matthew J Silva; Stavros Thomopoulos Journal: Bone Date: 2019-11-12 Impact factor: 4.398
Authors: Kevin A Maupin; Paul Childress; Alexander Brinker; Faisal Khan; Irushi Abeysekera; Izath Nizeet Aguilar; David J Olivos; Gremah Adam; Michael K Savaglio; Venkateswaran Ganesh; Riley Gorden; Rachel Mannfeld; Elliott Beckner; Daniel J Horan; Alexander G Robling; Nabarun Chakraborty; Aarti Gautam; Rasha Hammamieh; Melissa A Kacena Journal: NPJ Microgravity Date: 2019-09-24 Impact factor: 4.415