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This study aimed to investigate the impact of the dosage and duration of fluoride and aluminum(F and Al) co-exposure on the skeletal growth and bone quality of juvenile rats. Forty-eight 8-week-old Sprague-Dawley rats were randomly assigned to normal control, low F and Al exposure, and high F and Al exposure groups, with 45-day and 90-day subgroups established for each. We measured body length, tibia length, conducted bone histomorphometric analysis of the proximal tibia, performed micro-CT scans and three-point bending tests of the femur. Compared to the age-matched control group, the low F and Al group at 45 days exhibited increased bone formation and stiffness; the low F and Al group at 90 days and the high F and Al group at 45 days showed increases in body length, tibia length, growth plate width, longitudinal bone growth rate, bone turnover, and improved microstructure. Notably, bone elastic stress only elevated in the high F and Al group at 45 days. Conversely, the high F and Al exposure group at 90 days experienced decreases in the aforementioned parameters, with the exception of growth plate width, and displayed abnormal hypertrophic chondrocyte morphology in the growth plate. In summary, long-term exposure to low levels of F and Al and short-term exposure to high levels of F and Al promote bone formation followed by bone resorption in juvenile rats, stimulating bone growth and enhancing bone quality. However, long-term exposure to high levels F and Al results in low bone turnover, slow bone growth, and reduced bone property. • The co-exposure of fluoride and aluminum exhibits a dual effect, initially promoting and then inhibiting the functions of osteoblasts, osteoclasts, and chondrocytes. • Bone formation responds to fluoride and aluminum intake before resorption, with changes in resorption positively correlating to formation. • The co-exposure of fluoride and aluminum initially increases but subsequently inhibits or worsens the growth of long bones and bone quality in juvenile rats. [ABSTRACT FROM AUTHOR]

• Welsh onion (WO-H) and Portulaca oleracea (PO-H) increased femur and tibia lengths compared to the control in young rats. • The proliferative and hypertrophic zones of the growth plate were greater in the legs of WO-H and PO-H rats. • WO-H and PO-H reduced insulin resistance and PO-H had a better effect on it than the growth hormone injection. • WO-H and PO-H potentiated IGF-1 (pIRS-2 → pAkt) and TGF-β signaling in osteoblasts. • Longitudinal bone growth is associated with the improvement of insulin sensitivity. Longitudinal bone growth mainly occurs during adolescence and can be enhanced by growth hormones. We hypothesized that water extracts from roots of Allium fistulosum L. (Welsh onion, WO; 15 or 45 mg/kg bw/day) and Portulaca oleracea L. (PO; 15 or 45 mg/kg bw/day) can stimulate longitudinal bone growth in weanling male rats for 4 weeks. Femur and tibia lengths were higher in the WO-H and PO-H groups than in the control. The proliferative and hypertrophic zones of the growth plate were greater in the legs of WO-H and PO-H rats than in the control; a similar increase was observed in the positive-control (growth hormone, 20 μg/kg bw/day). WO-H and PO-H treatments were found to potentiate insulin-like growth factor-1 (IGF-1) signaling (pIRS-2 → pAkt) in MG-63 osteoblasts compared to control. WO-H and PO increased cell proliferation possibly by activating transforming growth factor (TGF)-β signaling via elevated BMP-2 and Smad4 expression in MG-63 cells. In conclusion, WO and PO are potential to promote the proliferation of the leg growth plate similar to growth hormone. [ABSTRACT FROM AUTHOR]

Abstract The effects of dietary supplementation with Antarctic krill oil (AKO) on longitudinal bone growth in adolescent male Institute for Cancer Research (ICR) mice for 21 days were investigated. Histological results showed that AKO promoted longitudinal bone growth, increased skeletal mineral content and strength, enhanced entochondrostosis supported by higher longitudinal bone growth rate and growth plate height. Then, the potential mechanisms responsible for these observations were measured, results showed that AKO increased the secretion of the GH-IGF-1 pathway and entochondrostosis-related factors in serum increased the expression of IGF-1 in the liver and bone, which promoted proliferation and differentiation of chondrocytes, vascular invasion and bone formation related gene expression. AKO promoted longitudinal bone growth, using the GH-IGF-1 pathway, suggesting that AKO might be a potential functional food to improve growth potential of adolescents. Graphical abstract Image 1 Highlights • Intake of Antarctic krill oil (AKO) greatly increased longitudinal bone growth. • AKO increased proliferative and hypertrophic zone heights in growth plate. • AKO increased the process of entochondrostosis. • AKO regulated bone growth of adolescent mice using the GH-IGF-1 pathway. [ABSTRACT FROM AUTHOR]