Aqueous Garlic Extract Alleviates Oxidative Stress and Inflammation in Retinal Tissue of Rats with Diabetes Type 2

Abstract:   

Background and Objective: Retinopathy is a common difficulty in diabetic subjects. Hyperglycemia damages the tissues through stimulation of oxidative stress and inflammation. Since the antioxidant function of garlic has been proven, in the current report the activity of aqueous garlic extract (AGE) upon the oxidative stress and inflammation in the retinal substances of rats with diabetes was investigated.
Materials and Methods: 24 male Wistar rats were distributed in 4 groups: the healthy rats,  the rats with diabetes (DM2),the garlic- treated rats with diabetes (DM2+AGE), and the garlic- treated healthy rats (AGE). After the treatment was finished, oxidative stress, total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), thiol group (SH), and lipid peroxidation (LPO) were assayed. For the evaluation of inflammation, mRNA and protein levels of transforming growth factor beta-2 (TGF-β2) and interleukin-1 beta (IL-1β) were measured in retinal homogenates using real-time PCR and ELISA, correspondingly.
Results: In  the DM2 rats, TAC and thiol group diminished (p<0.05 and p<0.001, respectively), whereas TOS and LPO increased (p<0.01 and p<0.001, correspondingly) compared to the control rats. In the DM2+AGE rats TAC and thiol group increased (p<0.01 and p<0.05, correspondingly), whereas TOS and LPO diminished (p<0.05 and p<0.001, correspondingly) compared with DM2 rats. The gene expression and protein concentrations of TGF-β2 and IL-1β increased in  the DM2 rats compared to the healthy group, whereas these parameters decreased in the DM2+AGE rats compared to the untreated rats with diabetes (p<0.001).
Conclusion: The findings revealed the antioxidant and anti-inflammatory results of garlic extract. Thus, garlic extract could be beneficial for lessening diabetes-induced retinopathy.

Keywords: Diabetes mellitus, Garlic extract, Inflammation, Oxidative stress, Retina