BACKGROUND:Skeletal muscle insulin resistance is the key pathological link of type 2 diabetes.The traditional Chinese medicine compound Roujishuncuiyin can effectively improve skeletal muscle insulin resistance,but its mechanism has not been clarified.OBJECTIVE:To explore the mechanism of Roujishuncuiyin on skeletal muscle insulin resistance in type 2 diabetes mice.METHODS:Forty db/db mice with type 2 diabetes mellitus were randomized into a model group,a low-dose Roujishuncuiyin group,a high-dose Roujishuncuiyin group,and a positive drug group,with 10 mice in each group.The latter three administration groups were given 157.5 mg/g and 630 mg/g Roujishuncuiyin and 200 mg/g metformin hydrochloride aqueous solution by gavage once a day,respectively.In addition,10 db/dm mice were selected as the blank control group.Mice in the model and blank control groups were given the same dose of 0.9％NaCl solution by gavage.After 12 weeks of intervention,fasting blood glucose was measured in each group of mice,and oral glucose tolerance test was performed to calculate the area under the blood glucose curve.ELISA was used to detect serum insulin level and calculate the resistance index.Mitochondrial structure of skeletal muscle tissue was observed under transmission electron microscopy.Western blot was used to detect the expression levels and phosphorylation levels of protein kinase B(AKT)and glycogen synthase kinase 3β(GSK-3β)proteins in skeletal muscle.RESULTS AND CONCLUSION:(1)Compared with the blank control group,fasting blood glucose,fasting insulin and insulin resistance index were significantly higher in the model group(P＜0.05),the area under the curve of the oral glucose tolerance test was significantly increased(P＜0.05),the expression of p-AKT and p-GSK3β proteins in tibialis anterior muscle was significantly decreased(P＜0.05),and there was a large amount of mitochondrial damage in tibialis anterior muscle and a large number of lipid droplets in the interstitium.(2)Compared with the model group,fasting blood glucose,fasting insulin,and insulin resistance index were significantly reduced in the low-and high-dose Roujishuncuiyin groups and the positive control group(P＜0.05),the area under the curve of the oral glucose tolerance test was reduced(P＜0.05),the expression of p-AKT and p-GSK3β proteins in the tibialis anterior muscle was significantly elevated(P＜0.05),and mitochondrial damage in the tibialis anterior muscle was significantly ameliorated,with decreased lipid droplets in the interstitium.(3)The above indexes were better in the high-dose Roujishuncuiyin group than the low-dose Roujishuncuiyin group(P＜0.05),while there was no significant difference between the high-dose Roujishuncuiyin group and positive control group(P＞0.05).To conclude,by upregulating the protein levels of p-AKT and p-GSK3β in skeletal muscle tissue,the traditional Chinese medicine compound Roujishuncuiyin can improve structural disorders and mitochondrial morphology in skeletal muscle tissue,reduce insulin resistance in the skeletal muscle and regulate glucose homeostasis in the body.

BACKGROUND:Skeletal muscle insulin resistance is the key pathological link of type 2 diabetes.The traditional Chinese medicine compound Roujishuncuiyin can effectively improve skeletal muscle insulin resistance,but its mechanism has not been clarified.OBJECTIVE:To explore the mechanism of Roujishuncuiyin on skeletal muscle insulin resistance in type 2 diabetes mice.METHODS:Forty db/db mice with type 2 diabetes mellitus were randomized into a model group,a low-dose Roujishuncuiyin group,a high-dose Roujishuncuiyin group,and a positive drug group,with 10 mice in each group.The latter three administration groups were given 157.5 mg/g and 630 mg/g Roujishuncuiyin and 200 mg/g metformin hydrochloride aqueous solution by gavage once a day,respectively.In addition,10 db/dm mice were selected as the blank control group.Mice in the model and blank control groups were given the same dose of 0.9％NaCl solution by gavage.After 12 weeks of intervention,fasting blood glucose was measured in each group of mice,and oral glucose tolerance test was performed to calculate the area under the blood glucose curve.ELISA was used to detect serum insulin level and calculate the resistance index.Mitochondrial structure of skeletal muscle tissue was observed under transmission electron microscopy.Western blot was used to detect the expression levels and phosphorylation levels of protein kinase B(AKT)and glycogen synthase kinase 3β(GSK-3β)proteins in skeletal muscle.RESULTS AND CONCLUSION:(1)Compared with the blank control group,fasting blood glucose,fasting insulin and insulin resistance index were significantly higher in the model group(P＜0.05),the area under the curve of the oral glucose tolerance test was significantly increased(P＜0.05),the expression of p-AKT and p-GSK3β proteins in tibialis anterior muscle was significantly decreased(P＜0.05),and there was a large amount of mitochondrial damage in tibialis anterior muscle and a large number of lipid droplets in the interstitium.(2)Compared with the model group,fasting blood glucose,fasting insulin,and insulin resistance index were significantly reduced in the low-and high-dose Roujishuncuiyin groups and the positive control group(P＜0.05),the area under the curve of the oral glucose tolerance test was reduced(P＜0.05),the expression of p-AKT and p-GSK3β proteins in the tibialis anterior muscle was significantly elevated(P＜0.05),and mitochondrial damage in the tibialis anterior muscle was significantly ameliorated,with decreased lipid droplets in the interstitium.(3)The above indexes were better in the high-dose Roujishuncuiyin group than the low-dose Roujishuncuiyin group(P＜0.05),while there was no significant difference between the high-dose Roujishuncuiyin group and positive control group(P＞0.05).To conclude,by upregulating the protein levels of p-AKT and p-GSK3β in skeletal muscle tissue,the traditional Chinese medicine compound Roujishuncuiyin can improve structural disorders and mitochondrial morphology in skeletal muscle tissue,reduce insulin resistance in the skeletal muscle and regulate glucose homeostasis in the body.