OBJECTIVE: Metal wear products cause the aseptic loosening of joint prosthesis. To investigate the effect of metal ions Co2+ and Cr3 on the osteoblast apoptosis, cell cycle distribution, and secretion of alkaline phosphatase (ALP), and to search a method to prevent and treat aseptic loosening. METHODS: The mouse calvarial osteoblasts (MC3T3-E1) were cultured in vitro to 3-5 generations (5 x 10(5) cells/mL) and divided into 2 groups: the experimental group and the control group. The osteoblasts were cultured in alpha-MEM medium containing 10% FBS (the control group), and the mixed solution of CoCl2 and CrCl was added after the osteoblasts cultured in alpha-MEM medium containing 10%FBS attached completely (the experimental group). At 12, 24, and 48 hours after culture, the osteoblast apoptosis and the cell cycle distribution were assessed by flow cytometry; and ELISA method was applied to detect ALP content in serum supernatant. RESULTS: At 12, 24, and 48 hours after culture, the apoptosis rates in the experimental group (13.90% +/- 0.52%, 14.80% +/- 0.41%, and 13.40% +/- 0.26%) were significantly higher than those in the control group (8.56% +/- 0.31%, 8.19% +/- 0.24%, and 2.15% +/- 0.11%), (P < 0.05); G2M (dividing phase) distribution ratio significantly decreased and G0G1 (dormancy stage) distribution ratio significantly increased when compared with those in the control group (P < 0.05); and the absorbency (A) values of ALP were 0.955 +/- 0.052, 0.624 +/- 0.041, and 0.498 +/- 0.026 in the experimental group, and were 1.664 +/- 0.041, 1.986 +/- 0.024, and 2.192 +/- 0.041 in the control group, showing significant differences between 2 groups (P < 0.05). CONCLUSION: Metal ions Co2+ and Cr3+ have a marked effect on osteoblasts cell cycle distribution, which can make most of the cells to be in dormancy stage (G0G1), up-regulate the apoptosis rate and inhibit the releasing of ALP from osteoblasts.
OBJECTIVE:Metal wear products cause the aseptic loosening of joint prosthesis. To investigate the effect of metal ions Co2+ and Cr3 on the osteoblast apoptosis, cell cycle distribution, and secretion of alkaline phosphatase (ALP), and to search a method to prevent and treat aseptic loosening. METHODS: The mouse calvarial osteoblasts (MC3T3-E1) were cultured in vitro to 3-5 generations (5 x 10(5) cells/mL) and divided into 2 groups: the experimental group and the control group. The osteoblasts were cultured in alpha-MEM medium containing 10% FBS (the control group), and the mixed solution of CoCl2 and CrCl was added after the osteoblasts cultured in alpha-MEM medium containing 10%FBS attached completely (the experimental group). At 12, 24, and 48 hours after culture, the osteoblast apoptosis and the cell cycle distribution were assessed by flow cytometry; and ELISA method was applied to detect ALP content in serum supernatant. RESULTS: At 12, 24, and 48 hours after culture, the apoptosis rates in the experimental group (13.90% +/- 0.52%, 14.80% +/- 0.41%, and 13.40% +/- 0.26%) were significantly higher than those in the control group (8.56% +/- 0.31%, 8.19% +/- 0.24%, and 2.15% +/- 0.11%), (P < 0.05); G2M (dividing phase) distribution ratio significantly decreased and G0G1 (dormancy stage) distribution ratio significantly increased when compared with those in the control group (P < 0.05); and the absorbency (A) values of ALP were 0.955 +/- 0.052, 0.624 +/- 0.041, and 0.498 +/- 0.026 in the experimental group, and were 1.664 +/- 0.041, 1.986 +/- 0.024, and 2.192 +/- 0.041 in the control group, showing significant differences between 2 groups (P < 0.05). CONCLUSION:Metal ions Co2+ and Cr3+ have a marked effect on osteoblasts cell cycle distribution, which can make most of the cells to be in dormancy stage (G0G1), up-regulate the apoptosis rate and inhibit the releasing of ALP from osteoblasts.