Vascular endothelial growth factor(VEGF) is a kind of protein facilitating the angiogenesis,which can combine with its special receptor. The 2 major functions of VEGF are:(1) accelerate the proliferation of endothelial cells,leading to the formation of new vessels;(2) up regulation of the vessels permeability.The activity of the VEGF is regulated by various factors at different levels,such as: hypoxia, oncogene,the cytokine, the intercellular matrix, etc .The biological character and role of VEGF were summarized in this article with special emphasis on VEGF function and regulation.

BACKGROUND:Rotator cuff muscle degeneration(muscle atrophy,fibrosis and fatty infiltration)is a common condition after rotator cuff tears,which seriously affects shoulder function and surgical outcomes.Ginsenoside Rg1 has biological effects such as anti-oxidation,anti-apoptosis and lipid-lowering.However,the effect of ginsenoside Rg1 on muscle degeneration after rotator cuff tear has not been reported. OBJECTIVE:To investigate the effect of ginsenoside Rg1 on muscle degeneration after massive rotator cuff tear in mice. METHODS:Sixty C57BL/6J mice were randomly divided into sham group,model group,ginsenoside Rg1 low dose group and ginsenoside Rg1 high dose group,with 15 mice in each group.The skin of the right shoulder of mice in the sham group was cut and sutured.Massive rotator cuff tear mouse models of the right shoulder were established in the other three groups.Supraspinatus tendon and suprascapular nerve compression were administrated.Mice in the sham and model groups were intraperitoneally injected with 0.5 mL of saline after operation,while those in the ginsenoside Rg1 low and high dose groups were intraperitoneally injected with ginsenoside Rg1 30 and 60 mg/kg respectively,once a day,for 6 weeks.Mice were assessed for limb function by gait analysis the day after the last injection.After euthanasia,the supraspinatus muscle on the operated side was taken to measure the muscle atrophy rate and muscle contractility.Muscle tissue was stained with oil red O and Masson.RT-PCR was used to detect the expression of atrophy,fibrosis,and fatty infiltration related genes. RESULTS AND CONCLUSION:Compared with the model group,low-and high-dose ginsenoside Rg1 significantly increased paw print area and step length(P<0.05).Compared with the model group,low-and high-dose ginsenoside Rg1 significantly increased myofiber cross-sectional area and supraspinatus contractility(P<0.05),and significantly decreased wet muscle mass reduction ratio,fatty infiltration area ratio,and collagen fiber area ratio(P<0.05).Compared with the model group,low-and high-dose ginsenoside Rg1 significantly decreased the expression of atrophy,fibrosis,and fatty infiltration related genes(P<0.05).There was no significant difference in paw print area,supraspinatus muscle contractility,and myofiber cross-sectional area between ginsenoside Rg1 low and high dose groups(P>0.05),and all other indexes were better in the ginsenoside Rg1 high dose group than in the ginsenoside Rg1 low dose group(P<0.05).To conclude,ginsenoside Rg1 could significantly reduce muscle atrophy,fibrosis and fatty infiltration following massive rotator cuff tear in mice,which is beneficial to improve muscle strength and limb function.