Advanced glycation end products modulate osteoclastic acidification by inhibiting the expression of V-ATPase a3 and CIC-7 / 中国组织工程研究

ABSTRACT

BACKGROUND:The effect of advanced glycation end products (AGEs) on bone resorption is controversial. Our previous study has shown that bone resorption is significantly inhibited when AGEs present with pre-osteoclast cells RAW 264.7, while the effect of AGEs on osteoclastic acidification remains unknown. OBJECTIVE:To investigate the effect of AGEs on osteoclastic acidification and the underlying mechanism. METHODS:RAW 264.7 cells were induced by RANKL (15μg/L;normal group) to generate osteoclasts, and AGEs (50-400 mg/L;experimental group) or bovine serum albumin (100 mg/L;control group) were added at the beginning of the induction. The effect of AGEs on bone resorption was evaIuated by anaIyzing the area of bone resorption on the Osteo Assay Surface plates, and the effect of AGEs on osteoclastic acidification was evaluated by acridine orange staining. Furthermore, the expression levels of V-ATPase a3 and CIC-7 were detected to investigate the underlying mechanism. RESULTS AND CONCLUSION:The bone resorption area in the AGEs group was significantly decreased compared with the normal group (P<0.05). Acridine orange staining reveaIed that the red fluorescence (620 nm) intensity in the AGEs group was significantly decreased compared with the normal group (P<0.05), and this inhibitory effect became obvious with the increase of AGEs concentration. Immunocytochemistry, western blot assay and PCR findings showed that the expression levels of V-ATPase a3 and CIC-7 in the AGEs group were decreased significantly compared with the normal group (P<0.05). To conclude, AGEs exert inhibitory effect on osteoclastic acidification, probably by inhibiting the expression of V-ATPase a3 and CIC-7.