BACKGROUND:Oxidative stress is one of the main causes of osteoporosis,and reducing the level of oxidative stress with increasing antioxidant defense is an important research direction for the treatment of osteoporosis.Studies have confirmed that astragaloside IV has anti-osteoporosis effects,but its mechanism of action is not clear.OBJECTIVE:To investigate the osteogenic effect of astragaloside IV in MC3T3-E1 cells under oxidative stress conditions.METHODS:MC3T3-E1 cells were randomly divided into four groups:the control group was cultured in a complete medium;the model group was cultured in the complete medium containing hydrogen peroxide which was replaced with another complete medium after 24 hours of intervention;the astragaloside IV group was cultured with the complete medium containing hydrogen peroxide and astragaloside IV which was replaced with another complete medium containing astragaloside IV after 24 hours of intervention;and the inhibitor group was cultured in the complete medium containing hydrogen peroxide,astragaloside IV,and extracellular signal-regulated kinases(ERK)inhibitor which was replaced with complete medium containing hydrogen peroxide,astragaloside IV,and ERK inhibitor after 24 hours of intervention.After 48 hours of intervention with hydrogen peroxide,malondialdehyde content was detected to evaluate the mitigating effect of astragaloside IV on the oxidative stress in MC3T3-E1 cells.Osteogenic induction was performed after 48 hours of intervention with hydrogen peroxide,and the osteogenic and mineralizing ability of MC3T3-E1 cells was verified by alkaline phosphatase staining and alizarin red staining;the expression of osteogenesis-related genes was detected by RT-qPCR;and the expression of osteogenesis-related proteins and ERK/AMP-activated protein kinase(AMPK)signaling pathway proteins was detected by western blot.RESULTS AND CONCLUSION:The intracellular alkaline phosphatase content and mineralized nodule formation were less in the model group than in the control group(P<0.05),and were more in the astragaloside IV group than in the model group(P<0.05).Compared with the control group,intracellular malondialdehyde content increased in the model group(P<0.05),mRNA and protein expression of osteocalcin,RUNX2,and type Ⅰ collagen decreased(P<0.05),and AMPK mRNA and p-AMPK protein expressions were elevated(P<0.05);compared with the model group,intracellular malondialdehyde content in the astragaloside IV group decreased(P<0.05),the mRNA and protein expressions of osteocalcin,RUNX2,and type Ⅰ collagen were elevated(P<0.05),the mRNA expressions of ERK1/2 and AMPK were elevated(P<0.05),and the protein expressions of p-AMPK and p-ERK1/2 were elevated(P<0.05).Additionally,ERK inhibitors partially inhibited the above effects of astragaloside IV.To conclude,astragaloside IV can promote osteogenic differentiation of MC3T3-E1 cells by activating the ERK/AMPK pathway.

BACKGROUND:Oxidative stress is one of the main causes of osteoporosis,and reducing the level of oxidative stress with increasing antioxidant defense is an important research direction for the treatment of osteoporosis.Studies have confirmed that astragaloside IV has anti-osteoporosis effects,but its mechanism of action is not clear.OBJECTIVE:To investigate the osteogenic effect of astragaloside IV in MC3T3-E1 cells under oxidative stress conditions.METHODS:MC3T3-E1 cells were randomly divided into four groups:the control group was cultured in a complete medium;the model group was cultured in the complete medium containing hydrogen peroxide which was replaced with another complete medium after 24 hours of intervention;the astragaloside IV group was cultured with the complete medium containing hydrogen peroxide and astragaloside IV which was replaced with another complete medium containing astragaloside IV after 24 hours of intervention;and the inhibitor group was cultured in the complete medium containing hydrogen peroxide,astragaloside IV,and extracellular signal-regulated kinases(ERK)inhibitor which was replaced with complete medium containing hydrogen peroxide,astragaloside IV,and ERK inhibitor after 24 hours of intervention.After 48 hours of intervention with hydrogen peroxide,malondialdehyde content was detected to evaluate the mitigating effect of astragaloside IV on the oxidative stress in MC3T3-E1 cells.Osteogenic induction was performed after 48 hours of intervention with hydrogen peroxide,and the osteogenic and mineralizing ability of MC3T3-E1 cells was verified by alkaline phosphatase staining and alizarin red staining;the expression of osteogenesis-related genes was detected by RT-qPCR;and the expression of osteogenesis-related proteins and ERK/AMP-activated protein kinase(AMPK)signaling pathway proteins was detected by western blot.RESULTS AND CONCLUSION:The intracellular alkaline phosphatase content and mineralized nodule formation were less in the model group than in the control group(P<0.05),and were more in the astragaloside IV group than in the model group(P<0.05).Compared with the control group,intracellular malondialdehyde content increased in the model group(P<0.05),mRNA and protein expression of osteocalcin,RUNX2,and type Ⅰ collagen decreased(P<0.05),and AMPK mRNA and p-AMPK protein expressions were elevated(P<0.05);compared with the model group,intracellular malondialdehyde content in the astragaloside IV group decreased(P<0.05),the mRNA and protein expressions of osteocalcin,RUNX2,and type Ⅰ collagen were elevated(P<0.05),the mRNA expressions of ERK1/2 and AMPK were elevated(P<0.05),and the protein expressions of p-AMPK and p-ERK1/2 were elevated(P<0.05).Additionally,ERK inhibitors partially inhibited the above effects of astragaloside IV.To conclude,astragaloside IV can promote osteogenic differentiation of MC3T3-E1 cells by activating the ERK/AMPK pathway.

This research focused on the doctors' changes based on the performance-payment reform from a district public hospital of Chongqing.The work compared the doctors' work efficiency,medical quality,scientific research,new technology and new project,cost control and patients burden.Performance-payment reform significantly activated doctors' self-study initiative and quality.The main running quotas of hospital,including stuff's positivity,work efficiency,medical quality,scientific research,new technology and new project,presented a better improvement trend.This not only reduced the patient cost burden,relieved the doctor-patient relationship,but also improved the hospital personnel cohesion,and strengthened the core competitiveness of the hospital.