Effect of Lead Nanoparticles Inhalation on Bone Calcium Sensing Receptor, Hydroxyapatite Crystal and Receptor Activator of Nuclear Factor-Kappa B in Rats.

This study aimed to investigate whether Pb nanoparticle exposure affects the bone calcium sensing receptor (CaSR), hydroxyapatite crystal, and receptor activator of nuclear factor-kappa B (RANK) in rats exposed to subchronic and chronic inhalation. Thirty two rats were randomly divided into eight groups. One group is a non-exposed group. While three groups were exposed to nanoparticles Pb at the following doses 6.25; 12.5; or 25 mg/m3 an hour daily for 28 days. Another three groups were exposed to nanoparticles Pb at following doses 6.25; 12.5; and 25 mg/m3 one hour daily for 6 months. The expression of trabecular CaSR was significantly decreased at the all doses subchronic exposure compared to the control group (P < 0.05). The CaSR expression significantly decreased in second and third doses subchronic exposure groups compared to the control groups (P < 0.05). With subchronic exposure, the crystal size was increased in second dose group and decreased in lowest and highest doses compared to the control (untreated) group. The crystal size and c-axis were decreased in all dose chronic exposures compared to the control (untreated) group. The expression of cortical RANK was significantly lower at the two lowest dose chronic exposures compared to the control group (P < 0.05). In conclusion, Pb nanoparticle inhibit hydroxyapatite crystal growth at least a part via down regulation of CaSR and RANK.

Final Declaration of the Asian Metaforum on the Role of Vitamin D and the Management of Osteoporosis.

BACKGROUND: Vitamin D is essential for Ca absorption, prevention of falls and fracture, and maintenance of muscle strength and balance. Lack of awareness of the importance of vitamin D in bone health is common in Asia. OBJECTIVE: To define key statements, objectives and actions for improving osteoporosis management and vitamin D inadequacy in Asia. RESULTS AND CONCLUSION: This declaration was jointly produced by specialists at the Asia Metaforum on the Role of Vitamin D and the Management of Osteoporosis, held in September 2006 in Hong Kong, to define actions to prevent vitamin D insufficiency in Asia. Although developed specifically for Asia, some or all of these statements may be applicable to other regions of the world.