The protective effect of pomegranate peel aqueous extract on selenite-induced cataract in rats.

The present study was performed to evaluate the preventive effect of pomegranate peel extract on sodium-induced cataract in rats. Sprague-Dawley suckling male rats were divided into four groups: group C: rats received no treatment, group P: rats received pomegranate peel aqueous extract (PPE) orally, group Se: rats received an injection of sodium selenite, group Se + P: rats received PPE and sodium selenite concomitantly. After 4 weeks, rats were sacrificed, and their lenses were homogenized and evaluated for biochemical parameters and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the Se group, developed cataract with significant lens opacity was observed. Other changes in enzymatic and non-enzymatic antioxidants, oxidative parameters, solubility of proteins, in NO and Ca levels and the electrophoresis pattern of proteins were observed in lenses of the Se group compared to control groups. After the preventive administration of PPE, most of these parameters were normalized due to antioxidant and anti-inflammatory activities of the extract. PRACTICAL APPLICATIONS: Cataract is one of the leading causes of vision impairment among the elderly, and surgery is the major therapeutic step taken to cure it. However, surgery has its limitations and complications. Therefore, prevention of cataract development, especially in high-risk individuals, can be better than cure. Pomegranate peel extract has a high potential to prevent cataract in these people.

Anti-cataract effects of Dajizhi (Euphorbium) eye drops on selenite-induced cataracts in rat.

OBJECTIVE: To evaluate the effects of Dajizhi (Euphorbium) on selenite-induced cataracts. METHODS: Wistar rat pups were divided into 9 groups. Rats in group 1 were subcutaneously injected with saline, and rats in the other groups were injected with sodium-selenite. Every right eye was treated with 5 µL eye drops 3 times per day, and the left eye received no treatment. The eyes of rats in group 3 were treated with pirenoxine; rats in groups 4, 5, 6, 7, 8 and 9 were respectively treated with Dajizhi (Euphorbium) (25 mg/mL), Dajizhi (Euphorbium) (5 mg/mL), Dajizhi (Euphorbium) methanol extract (25 mg/mL), Dajizhi (Euphorbium) methanol extract (5 mg/mL), euphol (25 mg/mL), euphol (5 mg/mL). Cataracts were observed by a slit lamp before and after treatment. Electroretinograms were acquired at set intervals. The morphological changes of the rat eyes were observed in vitro, and the levels of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in the lenses and aqueous humour were estimated at set intervals. RESULTS: Slit lamp examination showed decreased degrees of cataracts after administration of the different treatments. Morphological comparison showed that Dajizhi (Euphorbium) can reduce the turbidity of the lenses, meaning that Dajizhi (Euphorbium) has the anti-cataract effects. Low-concentration of Dajizhi (Euphorbium), its methanol extract and euphol treatment prevented the b-wave amplitudes of the electroretinograms from falling. Euphorbium treatment significantly restored GSH-Px and SOD levels in the lenses and aqueous humour, especially after 10 and 25 d of administration. Euphorbium may help lenses fight oxidative stress caused by selenite. CONCLUSION: The administration of Dajizhi (Euphorbium) can inhibit selenite-induced cataracts.

A Caenorhabditis elegans ortholog of human selenium-binding protein 1 is a pro-aging factor protecting against selenite toxicity.

Human selenium-binding protein 1 (SELENBP1) was originally identified as a protein binding selenium, most likely as selenite. SELENBP1 is associated with cellular redox and thiol homeostasis in several respects, including its established role as a methanethiol oxidase that is involved in degradation of methanethiol, a methionine catabolite, generating hydrogen sulfide (H2S) and hydrogen peroxide (H2O2). As both H2S and reactive oxygen species (such as H2O2) are major regulators of Caenorhabditis elegans lifespan and stress resistance, we hypothesized that a SELENBP1 ortholog in C. elegans would likely be involved in regulating these aspects. Here we characterize Y37A1B.5, a putative selenium-binding protein 1 ortholog in C. elegans with 52% primary structure identity to human SELENBP1. While conferring resistance to toxic concentrations of selenite, Y37A1B.5 also attenuates resistance to oxidative stress and lowers C. elegans lifespan: knockdown of Y37A1B.5 using RNA interference resulted in an approx. 10% increase of C. elegans lifespan and an enhanced resistance against the redox cycler paraquat, as well as enhanced motility. Analyses of transgenic reporter strains suggest hypodermal expression and cytoplasmic localization of Y37A1B.5, whose expression decreases with worm age. We identify the transcriptional coregulator MDT-15 and transcription factor EGL-27 as regulators of Y37A1B.5 levels and show that the lifespan extending effect elicited by downregulation of Y37A1B.5 is independent of known MDT-15 interacting factors, such as DAF-16 and NHR-49. In summary, Y37A1B.5 is an ortholog of SELENBP1 that shortens C. elegans lifespan and lowers resistance against oxidative stress, while allowing for a better survival under toxic selenite concentrations.

Impediment of selenite-induced cataract in rats by combinatorial drug laden liposomal preparation.

Cataract is the leading cause of blindness globally with surgery being the only form of treatment. But cataract surgery is accompanied by complications, chiefly intra-ocular infections. Hence, preventive nanoformulations may be extremely beneficial. In the present study, novel chitosan-coated liposomal formulations encapsulating a combination of drugs, lanosterol and hesperetin were prepared and characterized. The combinatorial liposomes were prepared by thin film evaporation active extrusion method. The characterization of liposomes was done by transmission electron microscopy, zeta potential, encapsulation efficiency, stability, cytotoxicity and in vitro release studies. The main difference between the chitosan-coated and uncoated combinatorial liposomes is the release of drugs as indicated by the in vitro release studies. The slow and sustained release of the drugs from chitosan-coated ones as against the burst release from uncoated indicates an increased retention time for combinatorial drugs in cornea. This leads to a delay in progression of cataract as seen from in vivo studies. Cytotoxicity studies indicate no cell toxicity of the coating of chitosan or the combination of drugs. Stability studies indicate that there were almost no changes in size, zeta potential and polydispersity index values of the combinatorial liposomes upon storage at room temperature for 60 days. Another important study is the estimation of antioxidant defense system. The estimated values of glutathione reductase, malondialdehyde and chief antioxidant enzymes point toward an upregulation of antioxidant defense system. From the results, it may be concluded that novel chitosan-coated combinatorial liposomes are effective in delaying or preventing of cataract.

Inhibitory effects of grape seed proanthocyanidin extract on selenite-induced cataract formation and possible mechanism.

This study investigated the inhibitory effect of grape seed proanthocyanidin extract (GSPE) on selenite-induced cataract formation in rats and the possible mechanism. Eighty 8-day-old Sprague-Dawley rats were divided randomly into 5 groups: control group, model group, three GSPE groups (low dose, medium dose and high dose). Control group received subcutaneous injection of physiological saline. Model group was given subcutaneous injection of sodium selenite (20 µmol/kg body weight) on the postpartum day 10, and once every other day for consecutive three times thereafter. GSPE treated groups were respectively administered GSPE at doses of 50, 100, and 200 mg/kg body weight intragastrically 2 days prior to the selenite injection (that was, on the postpartum day 8), and once daily for fourteen consecutive days thereafter. The opacity of lenses was observed, graded and photographed under the slit lamp microscopy and the maximal diameter of the nuclear cataract plaques was measured. The lenses were analyzed for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), malondialdehyde (MDA), calcium (Ca(2+)), nitric oxide (NO) and anti-hydroxyl radical ability (anti-OH(-)). The histomorphology of lenses was observed with HE staining under a light microscope. The levels of calpainII, and iNOS protein and mRNA expression in lenses were detected by using immunohistochemistry and real-time quantitative RT-PCR. The results showed subcutaneous injection of sodium selenite led to severe nuclear cataract in model group, and the achievement ratio of model group was 100%. As compared with model group, the degree of lenses opacity and the maximal diameter of nuclear cataract plaques were significantly reduced in GSPE-treated groups. Moreover, we observed selenite treatment caused a significant decrease in the activities of antioxidative enzymes (SOD, CAT, GSH-PX) and anti-OH(-) ability, accompanied by a significant increase in the levels of MDA, NO, Ca(2+) as well as iNOS, and calpainII protein and mRNA expression. Administration of GSPE could dose-dependently preserve the activities of these antioxidative enzymes and anti-OH(-) ability, accompanied by a significant reduction in the levels of MDA, NO, Ca(2+) as well as iNOS, and calpainII protein and mRNA expression. These results suggested that GSPE markedly prevented selenite-induced cataract formation probably by suppressing the generation of lipid peroxidation and free radicals as well as the activation of iNOS, and calpainII in the lenses.