Momordica charantia extracts ameliorate insulin resistance by regulating the expression of SOCS-3 and JNK in type 2 diabetes mellitus rats

Abstract

Context: Momordica charantia L. (Cucurbitaceae) has long been widely used as a traditional remedy for diabetes mellitus in some countries. However, detailed antidiabetic mechanisms are largely unknown.

Objectives: This study clarified the ameliorating effects of M. charantia ethanol extracts (MCE) on the insulin resistance in type 2 diabetes mellitus (T2DM) rats.

Materials and methods: T2DM rat model was established by high-fat diet and streptozotocin (STZ) injection. Diabetic rats were randomized into five groups: the model control group (n = 8) (common diet), the high-fat diet metformin (50 mg/kg/d), and the three-dose MCE (100, 200, and 400 mg/kg/d) groups (n = 8 each). After 8  weeks, the fasting serum glucose, insulin, TNF-α, and IL-6 were measured, and the relevant factors of glucose and insulin were monitored by glycogen dyeing, RT-PCR, and western blot, respectively.

Results: The 8-week treatment of 400 mg/kg MCE significantly lowered body weight (330.1 versus 365.9 g), serum glucose (7.41 versus 16.63 mmol/L), insulin (12.06 versus 15.89 mIU/L), TNF-α (52.72 versus 81.83 ng/L), and IL-6 (104.81 versus 135.74 ng/L) in comparison with those of the diabetic control group (p < 0.05). It was the same for skeletal muscle glucose transporter 4 (GLUT-4) protein, and glycogen level, suppressor of cytokine signaling-3 (SOCS-3), c-Jun N-terminal kinase (JNK), and Akt expression at both protein and mRNA levels in liver (p < 0.05).

Conclusions: MCE can ameliorate insulin resistance in T2DM rats. This effect may be related to the regulation of mRNA and protein levels of SOCS-3 and JNK.

Keywords:

• Suppressor of cytokine signaling-3
• c-Jun N-terminal kinase
• liver glycogen
• TNF-α
• IL-6

Acknowledgements

This work was supported by Natural Science Foundation of Liaoning Province Science and Technology Department (Grant no. 20170540368) and Foundation of Liaoning Province Education Department (Grant no. L2012305).

Disclosure statement

The authors declare that there is no conflict of interests regarding the publication of this paper.