Inhibitory Effect of Crocin(s) on Lens α-Crystallin Glycation and Aggregation, Results in the Decrease of the Risk of Diabetic Cataract.

Fereshteh Bahmani,Arezou Ghahghaei,Seyed Aldavood,Seyedeh Bathaie

doi:10.3390/molecules21020143

Abstract

The current study investigates the inhibitory effect of crocin(s), also known as saffron apocarotenoids, on protein glycation and aggregation in diabetic rats, and α-crystallin glycation. Thus, crocin(s) were administered by intraperitoneal injection to normal and streptozotocin-induced diabetic rats. The cataract progression was recorded regularly every two weeks and was classified into four stages. After eight weeks, the animals were sacrificed and the parameters involved in the cataract formation were measured in the animal lenses. Some parameters were also determined in the serum and blood of the rats. In addition, the effect of crocin(s) on the structure and chaperone activity of α-crystallin in the presence of glucose was studied by different methods. Crocin(s) lowered serum glucose levels of diabetic rats and effectively maintained plasma total antioxidants, glutathione levels and catalase activity in the lens of the animals. In the in vitro study, crocin(s) inhibited α-crystallin glycation and aggregation. Advanced glycation end products fluorescence, hydrophobicity and protein cross-links were also decreased in the presence of crocin(s). In addition, the decreased chaperone activity of α-crystallin in the presence of glucose changed and became close to the native value by the addition of crocin(s) in the medium. Crocin(s) thus showed a powerful inhibitory effect on α-crystallin glycation and preserved the structure-function of this protein. Crocin(s) also showed the beneficial effects on prevention of diabetic cataract.

Highlights

Cloudiness of the natural lens is called a cataract
We studied the effect of crocin(s) on glycation of α-crystallin as a model protein of the lens in the absence and presence of glucose and crocin(s)
Crocin(s) had no cataractogenic effect on normal rats. These results indicated that crocin(s) treatment reduced the rate of cataract development in the diabetic group

Summary

Introduction

Cloudiness of the natural lens is called a cataract. Cataracts remain a major cause of visual disability and blindness worldwide and their prevalence in diabetic patients is fivefold higher than among non-diabetics [1]. Α-Crystallin is a major structural protein of the vertebrate eye lens This water-soluble protein is a member of the small heat shock protein family and has been known as a molecular chaperone in the eye lens. It inhibits the aggregation and inactivation of several other lens proteins and enzymes and plays an important role in maintaining the transparency of the lens [4]. Non-enzymatic glycation and oxidation of lens proteins and reduction in the chaperone function of α-crystallin have been reported previously in diabetic conditions [7,8].

Objectives

Methods

Results

Discussion

Conclusion