[Hypoglycemic effect of electroacupuncture at "Tianshu" (ST 25) combined with metformin on rats with type 2 diabetes mellitus based on AMPK].

Abstract

To observe the hypoglycemic effect of electroacupuncture (EA) at "Tianshu" (ST 25) combined with metformin on rats with type 2 diabetes mellitus (T2DM) as well as its effect on expression of adenosine monophosphate activated protein kinase (AMPK) in liver and pancreas. Thirty-six male SD rats were randomly divided into a blank group (6 rats) and a model establishing group (30 rats). The rats in the model establishing group were fed with high-fat diet and treated with intraperitoneal injection of low-dose streptozotocin (STZ) to establish T2DM model. The rats with successful model establishment were randomly divided into a model group, a control group, a metformin group, an EA group and a combination group, 6 rats in each group. The rats in the EA group were treated with EA at "Tianshu" (ST 25), dense-disperse wave, 2 Hz/15 Hz in frequency and 2 mA in current intensity, 20 min each time. The rats in the metformin group were treated with intragastric administration of metformin (190 mg/kg) dissolved in 0.9% sodium chloride solution (2 mL/kg). The rats in the combination group were treated with EA at "Tianshu" (ST 25) and intragastric administration of metformin. The rats in the control group were treated with intragastric administration of 0.9% sodium chloride solution with the same dose. All the treatments were given once a day for 5 weeks. After the intervention, the body mass and random blood glucose were detected; the serum insulin level was detected by ELISA; the expression of AMPK and phosphorylated adenosine monophosphate activated protein kinase (p-AMPK) in liver and pancreas was detected by Western blot method; the expression of protein gene product 9.5 (PGP9.5) was detected by immunofluorescence. ①Compared with the blank group, the body mass in the model group was decreased (P<0.05); compared with the model group, the body mass in the EA group and the combination group was decreased (P<0.05); the body mass in the EA group and the combination group was lower than the metformin group (P<0.05). Compared with the blank group, the random blood glucose in the model group was increased (P<0.01); compared with the model group, the random blood glucose in the metformin group, the EA group and the combination group was decreased (P<0.01). The random blood glucose in the combination group was lower than the metformin group and the EA group (P<0.05). ②Compared with the blank group, the insulin level in the model group was decreased (P<0.05); compared with the model group, the insulin level in the metformin group, the EA group and the combination group was all increased (P<0.05). The insulin level in the combination group was higher than the metformin group and the EA group (P<0.05). ③Compared with the blank group, the protein expression of AMPK and p-AMPK in liver tissue was decreased (P<0.05), and the protein expression of AMPK and p-AMPK in pancreatic tissue was increased (P<0.05) in the model group. Compared with the model group, the protein expression of AMPK and p-AMPK in liver tissue in the metformin group, the EA group and the combination group was increased (P<0.05, P<0.01); the protein expression of AMPK in pancreatic tissue in the metformin group was increased (P<0.05); the protein expression of AMPK in pancreatic tissue in the EA group and the combination group was decreased (P<0.05); the protein expression of p-AMPK in pancreatic tissue in the metformin group, the EA group and the combination group was decreased (P<0.05). The protein expression of AMPK and p-AMPK in liver tissue in the combination group was higher than that in the metformin group and the EA group (P<0.05); the protein expression of AMPK in pancreatic tissue in the EA group and the combination group was less than that in the metformin group (P<0.05), and the expression of p-AMPK protein in pancreatic tissue in the combination group was less than that in the metformin group and the EA group (P<0.05). ④Compared with the blank group, the expression of PGP9.5 in pancreatic tissue in the model group was increased (P<0.01); compared with the model group, the expression of PGP9.5 in pancreatic tissue in the metformin group, the EA group and the combination group was decreased (P<0.05, P<0.01). The expression of PGP9.5 in pancreatic tissue in the EA group was lower than the metformin group and the combination group (P<0.05). Electroacupuncture at "Tianshu" (ST 25) could promote the effect of metformin on activating AMPK in liver tissue of T2DM rats, improve the negative effect of metformin on AMPK in pancreatic tissue, and enhance the hypoglycemic effect of metformin. The mechanism may be related to the inhibition of pancreatic intrinsic nervous system.