Salvia miltiorrhiza prevents iron overload-induced apoptosis and decline of osteogenic capacity of MC3T3-E1 by blocking p38 mitogen-activated protein kinase signaling

Abstract

Objective To study salvia miltiorrhiza (SM) whether or not can prevent iron overload-induced apoptosis and the decline of osteogenic differentiation and mineralization of MC3T3-E1 preosteoblast, and examine the mechanism. Methods MC3T3-E1 was treated with Femc ammonium citrate (FAC, group F), or with FAC and SM in different concentrations (group DF1, DF2, DF3). the mineralization of MC3T3-E1 was examined by alizarin red staining, the apoptosis rate of the cells was examined by flow cytometry. The mRNA expressions of osteocalcin (BGP), runt related transcription factor-2 (RUNX2) and type 1 collagen α (COL1A) were examined by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR). The protein expression of p-p38 were detected by Western blotting. Results The generation rate of calcium nodes of group DF2 was higher than group F observably according to alizarin red staining. The apoptosis rate of group DF1, DF2, DF3 were much lower than group F (2.68±0.60)%, (2.21±0.49)%, (1.35±0.11)% vs. (8.34±0.31)% respectively (F=145.160, P=0.000). The relative expression of osteogenesis-related genes (BGP, Runx2, COL1A) of different groups had higher level than group F: (1.95±0.04, 2.08±0.17, 2.78±0.10 vs. 0.78±0.08; 0.64±0.02, 0.75±0.02, 0.83±0.03 vs. 0.58±0.02; 0.39±0.02, 0.74±0.02, 0.94±0.02 vs. 0.35±0.03 respectively). Compared to the group treated with FAC, the protein expression level of p-p38 of group treated with FAC and SM was significantly rised (0.42±0.03 vs. 0.30±0.01, F=126.370, P=0.000). Conclusion Salvia miltiorrhiza can prevent iron overload-induced apoptosis of MC3T3-E1, meanwhile reduce the decline of differentiation and mineralization. the mechanism is related to suppressing the p38 mitogen-activated protein kinase (MAPK) signal pathway. Key words: Salvia miltiorrhiza; Iron overload; MC3T3-E1 preosteoblast; p38