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Updated: Jul 16, 2025
Modeling and Evaluation of Murine Diabetic Cardiomyopathy Model
Published on: November 29, 2024
Effects of autophagy inhibitor 3-methyladenine on a diabetic mice model
Hai-Wen Ren1,2, Wen Yu1, Ya-Nan Wang1
1Health Science Center, Yangtze University, Jingzhou 434023, Hubei Province, China.
Aim:
To investigate the role of autophagy inhibitor 3-methyladenine (3-MA) on a diabetic mice model (DM) and the potential mechanism.
Methods:
Male C57BL/6J mice were randomly divided into a normal control group (NC group) and an DM group. DM were induced by multiple low-dose intraperitoneal injection of streptozotocin (STZ) 60 mg/kg·d for 5 consecutive days. DM mice were randomly subdivided into untreated group (DM group), 3-MA (10 mg/kg·d by gavage) treated group (DM+3-MA group) and chloroquine (CQ; 50 mg/kg by intraperitoneal injection) treated group (DM+CQ group). The fasting blood glucose (FBG) levels were recorded every week. At the end of experiment, retinal samples were collected. The expression levels of pro-apoptotic proteins cleaved caspase-3, cleaved poly ADP-ribose polymerase 1 (PARP1) and Bax, anti-apoptotic protein Bcl-2, fibrosis-associated proteins Fibronectin and type 1 collagen α1 chain (COL1A1), vascular endothelial growth factor (VEGF), inflammatory factors interleukin (IL)-1β and tumor necrosis factor (TNF)-α, as well as autophagy related proteins LC3, Beclin-1 and P62 were determined by Western blotting. The oxidative stress indicators 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) were detected by commercial kits.
Results:
Both 3-MA and CQ had short-term hypoglycemic effect on FBG and reduced the expression of VEGF and inflammatory factors IL-1β and TNF-α in DM mice. 3-MA also significantly alleviated oxidative stress indicators 8-OHdG and MDA, decreased the expression of fibrosis-related proteins Fibronectin and COL1A1, pro-apoptotic proteins cleaved caspase-3, cleaved PARP1, as well as the ratio of Bax/Bcl-2. CQ had no significant impact on the oxidative stress indicators, fibrosis, and apoptosis related proteins. The results of Western blotting for autophagy related proteins showed that the ratio of LC3 II/LC3 I and the expression of Beclin-1 in the retina of DM mice were decreased by 3-MA treatment, and the expression of P62 was further increased by CQ treatment.
Conclusion:
3-MA has anti-apoptotic and anti-fibrotic effects on the retina of DM mice, and can attenuate retinal oxidative stress, VEGF expression and the production of inflammatory factors in the retina of DM mice. The underlying mechanism of the above effects of 3-MA may be related to its inhibition of early autophagy and hypoglycemic effect.
Insights
The autophagy inhibitor 3-methyladenine (3-MA) demonstrates protective effects in diabetic mice retinas by reducing apoptosis, fibrosis, and inflammation. These benefits are linked to its ability to inhibit early autophagy and lower blood glucose levels.
Area of Science:
- Ophthalmology
- Diabetology
- Cell Biology
Background:
- Diabetic retinopathy is a leading cause of vision loss.
- Autophagy plays a complex role in diabetic complications.
- 3-methyladenine (3-MA) is an autophagy inhibitor with potential therapeutic applications.
Purpose of the Study:
- To investigate the therapeutic potential of 3-methyladenine (3-MA) in a mouse model of diabetic retinopathy (DM).
- To elucidate the underlying mechanisms of 3-MA's effects on retinal tissues in diabetic mice.
Main Methods:
- Diabetic mice (DM) were induced using streptozotocin (STZ).
- DM mice were treated with 3-MA or chloroquine (CQ).
- Retinal tissues were analyzed for markers of apoptosis, fibrosis, oxidative stress, inflammation, and autophagy via Western blotting and commercial kits.
Main Results:
- 3-MA and CQ reduced blood glucose and inflammatory markers (VEGF, IL-1β, TNF-α).
- 3-MA significantly decreased oxidative stress (8-OHdG, MDA), fibrosis (Fibronectin, COL1A1), and apoptosis (cleaved caspase-3, cleaved PARP1, Bax/Bcl-2 ratio).
- 3-MA reduced autophagy markers (LC3 II/LC3 I, Beclin-1) and increased P62, indicating early autophagy inhibition.
Conclusions:
- 3-MA exhibits anti-apoptotic and anti-fibrotic effects in the retinas of diabetic mice.
- 3-MA attenuates retinal oxidative stress, VEGF expression, and inflammation in diabetic mice.
- The protective mechanisms of 3-MA involve early autophagy inhibition and a hypoglycemic effect.
