Abstract:

BACKGROUND: When the people living on the plain go to the plateau, soon they would suffer low bone mass, if a bone fracture happens on the plateau, bone heal would be delayed, even nonunion. Comparing with the region of low altitude, bone absorption in the region of high altitude increases and bone mass decreases.
OBJECTIVE: To observe the effect of lower oxygen concentration on the differentiation of mouse osteoclast at different time points, and to study the possible molecule mechanisms of effect of hypoxia on the osteoclast differentiation.
METHODS: The mouse bone marrow cells were obtained from mice and were cultured in normoxia (20% oxygen concentration) and hypoxia (3% oxygen concentration) groups. The 3rd -5th generation mature osteoblasts were added to purified bone marrow cells. These cells were randomized into 2 groups with 4 samples in each group. At 1, 3, 5 and 7 days after cultivation, total cellular RNA was isolated using total RNA kit. RT-PCR was performed to detect the expression of osteoprotegerin and RANK and RANKLmRNA. The expression of RANK protein was assayed by Western blot.
RESULTS AND CONCLUSION: Compared with normoxia group, with time prolonged, the expression of osteoprotegerin mRNA was decreased but the expression of RANKmRNA, RANKLmRNA and RANK protein were increased. The results demonstrated that hypoxia can stimulate the differentiation of osteoclasts. Especially at the 5th day of lack of oxygen, the quantity of osteoclasts formation was greatest.