Effects of 4-phenylbutyric acid on the development of diabetic retinopathy in diabetic rats: regulation of endoplasmic reticulum stress-oxidative activation.

There are good evidences suggesting that endoplasmic reticulum (ER) stress can be one of the contributing factors in the development of diabetic retinopathy. The present study was designed to investigate the effect of chemical chaperone 4-phenylbutyric acid (4-PBA) in alleviating the ER stress, and diabetic retinopathy in type 2 diabetic rats. Treatment of diabetic rats with 4-PBA, increased the antioxidant capacity, reduced the levels of lipid peroxidation, organised the state of apoptosis and regulated the ER stress - oxidative activation in retinal tissue. Also there was an improvement in the histological picture of retinal specimens compared to untreated diabetic rats. It was concluded that 4-PBA is a promising therapeutic agent for ER stress diseases such as diabetic retinopathy.

Chromium-picolinate induced ocular changes: Protective role of ascorbic acid.

Chromium-picolinate (Cr-picolinate) is a popular nutritional supplement; however its safety has been questioned with regard to its ability to act as a clastogen. The aim of the present work was to evaluate the biochemical, histological and morphological changes in the cornea and lens following oral administration of Cr-picolinate and the possible protective effect of Vitamin C. Ninety male Sprague-Dawley rats were divided into five groups included the control group, the groups treated with Cr-picolinate (0.8 and 1.5 mg/100 g b.w.) alone or in combination with Vitamin C (0.5 mg/100 g b.w.) for 8 weeks. The results indicated that the high dose of Cr-picolinate induced a significant decrease in SOD, GSH, Na(+)-, K(+)-ATPase levels, and a significant increase in MDA level. Severe morphological and histological changes in the cornea and lens accompanied with a decrease in the total soluble protein of the lens homogenate and changes in the crystalline fractions in lens. Vitamin C supplementation succeeded to restore these changes to great extent. It could be concluded that consumption of Cr-picolinate for a long time induced several hazards to cornea and lens. Supplementation with extra amounts of Vitamin C may be useful to restrain the Cr-picolinate induced ocular changes.