Exendin-4 improves hepatocyte injury by decreasing proliferation through blocking NGF/TrkA in diabetic mice

Area of Science:

• Hepatology
• Endocrinology
• Neuroscience

Background:

• Hepatocytes express nerve growth factor (NGF) and its receptor tyrosine kinase A (TrkA).
• The role of the NGF/TrkA system in diabetic hepatocyte proliferation and the impact of exendin-4 remain unclear.

Purpose of the Study:

• To investigate the effect of exendin-4 on the NGF/TrkA system in the liver of diabetic mice.
• To explore exendin-4's influence on hepatocyte proliferation and oxidative stress markers in diabetes.

Main Methods:

• BALB/c mice were divided into four groups: control, exendin-4 alone, streptozotocin (STZ)-induced diabetes, and STZ + exendin-4.
• Exendin-4 (3 μg/kg daily for 30 days) was administered to diabetic mice.
• Assessed hepatocyte proliferation (PCNA), NGF, TrkA, p75NTR, caspase-3, liver enzymes (ALT, AST), oxidative stress markers (LPO, protein carbonyl, MPO), and antioxidant enzymes (catalase, SOD, GPx).

Main Results:

• Exendin-4 treatment in diabetic mice decreased NGF, TrkA, and PCNA-positive hepatocytes.
• p75 neurotrophin receptor and caspase-3 positive hepatocytes were undetectable.
• Exendin-4 reduced liver enzyme activities, lipid peroxidation, protein carbonyl, and myeloperoxidase levels.
• Antioxidant enzyme activities (catalase, SOD, GPx) and glutathione levels were increased.

Conclusions:

• Exendin-4 exhibits anti-proliferative effects on hepatocytes in diabetic mice.
• The mechanism involves blocking the NGF/TrkA signaling pathway.
• Exendin-4 also enhances the liver's oxidative defense system in diabetic conditions.