TY - JOUR
T1 - Nuclear factor erythroid 2–related factor 2 (Nrf2) deficiency causes age-dependent progression of female osteoporosis
AU - Kubo, Yusuke
AU - Beckmann, Rainer
AU - Pahlavani, Helda
AU - Saldivar, Mauricio Cruz
AU - Szymanski, Katharina
AU - Leeflang, Sander
AU - Mirzaali, Mohammad Javad
AU - Zadpoor, Amir Abbas
AU - Wruck, Christoph Jan
AU - Jahr, Holger
AU - More Authors, null
PY - 2022
Y1 - 2022
N2 - Background: Nuclear factor erythroid 2–related factor 2 (Nrf2) is a crucial transcription factor for cellular redox homeostasis. The association of Nrf2 with elderly female osteoporotic has yet to be fully described. The aim was to elucidate a potential age-dependent Nrf2 contribution to female osteoporosis in mice. Methods: Eighteen female wild type (WT) and 16 Nrf2-knockout (KO) mice were sacrificed at different ages (12 weeks = young mature adult and 90 weeks = old) to analyze their femurs. The morphological properties (trabecular and cortical) were evaluated by micro-computed tomography (μCT) and compared to gold standard histochemistry analysis. The quasi-static compression tests were performed to calculate the mechanical properties of bones. Additionally, the population of bone resorbing cells and aromatase expression by osteocytes was immunohistochemically evaluated and empty osteocyte lacunae was counted in cortical bone. Results: Old Nrf2-KO mice revealed a significantly reduced trabecular bone mineral density (BMD), cortical thickness, cortical area, and bone fraction compared to old WT mice, regardless of no significant difference in skeletally mature young adult mice between WT and KO. Specifically, while all old WT mice showed thin metaphyseal trabeculae, trabecular bone was completely absent in 60% of old KO mice. Additionally, old KO mice showed significantly more osteoclast-like cells and fewer aromatase-positive osteocytes than WT mice, whereas the occurrence of empty osteocyte lacunae did not differ between both groups. Nrf2-KO mice further showed an age-dependently reduced fracture resilience compared to age-matched WT mice. Conclusion: Our results suggest that chronic Nrf2 loss can lead to age-dependent progression of female osteoporosis.
AB - Background: Nuclear factor erythroid 2–related factor 2 (Nrf2) is a crucial transcription factor for cellular redox homeostasis. The association of Nrf2 with elderly female osteoporotic has yet to be fully described. The aim was to elucidate a potential age-dependent Nrf2 contribution to female osteoporosis in mice. Methods: Eighteen female wild type (WT) and 16 Nrf2-knockout (KO) mice were sacrificed at different ages (12 weeks = young mature adult and 90 weeks = old) to analyze their femurs. The morphological properties (trabecular and cortical) were evaluated by micro-computed tomography (μCT) and compared to gold standard histochemistry analysis. The quasi-static compression tests were performed to calculate the mechanical properties of bones. Additionally, the population of bone resorbing cells and aromatase expression by osteocytes was immunohistochemically evaluated and empty osteocyte lacunae was counted in cortical bone. Results: Old Nrf2-KO mice revealed a significantly reduced trabecular bone mineral density (BMD), cortical thickness, cortical area, and bone fraction compared to old WT mice, regardless of no significant difference in skeletally mature young adult mice between WT and KO. Specifically, while all old WT mice showed thin metaphyseal trabeculae, trabecular bone was completely absent in 60% of old KO mice. Additionally, old KO mice showed significantly more osteoclast-like cells and fewer aromatase-positive osteocytes than WT mice, whereas the occurrence of empty osteocyte lacunae did not differ between both groups. Nrf2-KO mice further showed an age-dependently reduced fracture resilience compared to age-matched WT mice. Conclusion: Our results suggest that chronic Nrf2 loss can lead to age-dependent progression of female osteoporosis.
KW - Bone strength
KW - Estrogen
KW - Fracture resilience
KW - Nrf2
KW - Osteoporosis
UR - http://www.scopus.com/inward/record.url?scp=85142528443&partnerID=8YFLogxK
U2 - 10.1186/s12891-022-05942-1
DO - 10.1186/s12891-022-05942-1
M3 - Article
AN - SCOPUS:85142528443
SN - 1471-2474
VL - 23
JO - BMC Musculoskeletal Disorders
JF - BMC Musculoskeletal Disorders
IS - 1
M1 - 1015
ER -