Antioxidant and anti-apoptotic effects of tocotrienol-rich fraction against streptozotocin-induced diabetic retinopathy in rats

• Published in: Biomedicine & pharmacotherapy 2022-09, Vol.153, p.113533-113533, Article 113533
• Main Authors: Sadikan, Muhammad Zulfiqah, Nasir, Nurul Alimah Abdul, Iezhitsa, Igor, Agarwal, Renu
• Format: Article
• Language: English
• Subjects: Diabetic retinopathy; Neurodegeneration; Oxidative stress; Tocotrienol-rich fraction; Visual behaviour
• ISSN: 0753-3322; 1950-6007
• DOI: 10.1016/j.biopha.2022.113533

Oxidative stress, a key player in diabetic retinopathy (DR), is associated with retinal cell apoptosis. This study investigated the effect of tocotrienol-rich fraction (TRF), a potent antioxidant, towards visual behaviour, retinal morphology, cells apoptosis and redox status in streptozotocin (STZ)-induced DR rats. Sprague-Dawley rats were divided into 3 groups: non-diabetic (N), was injected with citrate buffer intraperitoneally, diabetic treated with vehicle (DV), and diabetic treated with TRF (DT), were injected with STZ intraperitoneally (55 mg/kg) to induce diabetes. DT received 100 mg of TRF/kg orally for 12-weeks, whereas DV and N received vehicle. The general and visual-behaviour responses were assessed at week 12 in an open field arena. Rats were then sacrificed, and retinae were processed for haematoxylin and eosin (H&E) and terminal transferase-mediated dUTP nick end-labelling (TUNEL) staining. Retinal antioxidant, lipid peroxidation and anti-apoptotic markers were measured. The general and visual-behaviour responses in DT were comparable to N. Retinal thickness and cell counts were lower in DV and DT compared to N. Lower number of TUNEL-positive cells were observed in DT compared to DV (1.48-fold, p