Advanced glycation end products and diabetic complications

Effect of Low-Dose Gamma Radiation and Lipoic Acid on High- Radiation-Dose Induced Rat Brain Injuries

Aim

This work aims to investigate the possible radio-adaptive mechanisms induced by low-dose (LD) whole-body γ-irradiation alone or combined with alpha-lipoic acid (ALA) administration in modulating high-dose (HD) head irradiation–induced brain injury in rats.

Materials and Methods

Rats were irradiated with LD (.25 Gy) 24 hours prior HD (20 Gy), and subjected to ALA (100 mg/kg/day) 5 minutes after HD and continued for 10 days. At the end of the experiment, animals were sacrificed and brain samples were dissected for biochemical and histopathological examinations.

Results

HD irradiation-induced brain injury as manifested by elevation of oxidative stress, DNA damage, apoptotic, and inflammatory markers in brain tissue. Histological examination of brain sections showed marked alterations. However, LD alone or combined with ALA ameliorated the changes induced by HD.

Conclusion

Under the present experimental conditions, LD whole-body irradiation exhibited neuroprotective activity against detrimental effects of a subsequent HD head irradiation. This effect might be due to the adaptive response induced by LD that activated the anti-oxidative, anti-apoptotic, and anti-inflammatory mechanisms in the affected animals making them able to cope with the subsequent high-dose exposure. However, the combined LD exposure and ALA supplementation produced a further modulating effect in the HD-irradiated rats.

Distribution of advanced glycation end products and their receptor in the stomach of diabetic rats

AIM: To observe the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the stomach of diabetic rats.

METHODS: Diabetes mellitus (DM) and control (CON) rats were reared for eight weeks. Fasting plasma glucose (FPG), glycated serum protein (GSP) and gastric layer thickness were measured. The expression of AGEs and RAGE was detected by immunohistochemical staining.

RESULTS: The thickness of the mucosa (781.47 μm ± 137.82 μm vs 709.85 μm ± 169.41 μm) and submucosa (233.39 μm ± 134.05 μm vs 109.32 μm ± 44.43 μm) increased significantly in the DM group compared with the CON group (P < 0.05). The expression of AGEs and RAGE in the mucosa (5.66 ± 1.90 vs 2.25 ± 0.52, 2.79 ± 0.54 vs 1.70 ± 0.30) and muscle (37.37 ± 7.38 vs 24.32 ± 4.02, 4.26 ± 0.80 vs 3.59 ± 0.37) layers of the stomach was significantly higher in the DM group than in the CON group (P < 0.05).

CONCLUSION: The expression of AGEs and RAGE is up-regulated in the stomach of diabetic rats. The increased levels of AGE and RAGE in gastric tissue may contribute to diabetic gastrointestinal dysfunction.