Coothan Kandaswamy Veena

Evaluating the effect of sulphated polysaccharides on cyclosporine a induced oxidative renal injury.

Cyclosporine A (CsA) has been universally used as an immunosuppressant for the management of organ transplantation and various autoimmune diseases. However, nephrotoxicity due to CsA remains to be an important clinical challenge. In the present investigation, an attempt has been made to appraise the effect of sulphated polysaccharides on oxidative renal injury caused by CsA. Adult male Wistar rats were divided into four groups. Two groups received CsA by oral gavage (25 mg/kg body weight) for 21 days to provoke nephrotoxicity, one of which simultaneously received sulphated polysaccharides subcutaneously, (5 mg/kg body weight). A vehicle (olive oil) treated control group and sulphated polysaccharides drug control were also built-in. An increase in lipid peroxidation along with abnormal levels of enzymic (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glucose-6-phosphate dehydrogenase) and non-enzymic antioxidants (glutathione, vitamin C and vitamin E) are the salient features observed in CsA induced nephrotoxicity. CsA induced impairment of renal toxicity was evident from the marked decline in the activities of renal marker enzymes like alkaline phosphatase, acid phosphatase and lactate dehydrogenase, as well as an apparent increase in the serum urea, uric acid and creatinine; diagnostic of renal damage was normalized by sulphated polysaccharides co-administration. Sulphated polysaccharides treatment showed an effectual role in counteracting the free radical toxicity by bringing about a significant decrease in peroxidative levels and increase in antioxidant status. These observations emphasize the antioxidant property of sulphated polysaccharides and its cytoprotective action against CsA induced nephrotoxicity.

Counteracting adriamycin-induced oxidative stress by administration of N-acetyl cysteine and vitamin E

Abstract Adriamycin (ADR), a cytotoxic antineoplastic drug, is used in the treatment of various solid tumors. However, its efficacy continues to be challenged by significant toxicities including nephrotoxicity. In the present study, the effects of N-acetyl cysteine (NAC) and vitamin E, known antioxidants, were investigated on ADR-induced peroxidative damage in rat kidney. Adult male albino rats of Wistar strain were administered ADR as a single dose (10mg/kg body weight, i.v.). Histopathological studies indicated that ADR-treated kidney sections show focal tubular necrosis and casts. ADR-injected rats showed a significant decline in the activities/levels of enzymic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and glutathione-S-transferase) and non-enzymic antioxidants (thiols, vitamin C and vitamin E) with high malondialdehyde levels. The extent of nephrotoxicity was evident from the increased activities of urinary marker enzymes (alkaline phosphatase, lactate dehydrogenase and γ-glutamyltransferase). Treatment with NAC and vitamin E (50mg/kg b.w., i.p.) 1day prior to ADR administration maintained near normal activities of the enzymes, significantly reduced lipid peroxidation and prevented the necrosis caused by ADR, thereby proving to be an effective thiol replenishing agent and antioxidant.

Antiurolithic Effect of Lupeol and Lupeol Linoleate in Experimental Hyperoxaluria

The present study was undertaken to explore the efficiency of the pentacyclic triterpene lupeol (1) and its ester derivative, lupeol linoleate (2), in experimental hyperoxaluria. Hyperoxaluria was induced in male Wistar rats with 0.75% ethylene glycol (EG) in drinking water for 28 days. Hyperoxaluric animals were supplemented orally with 1 and 2 (50 mg/kg body wt/day) throughout the experimental period of 28 days. The renal enzymes were assayed as markers of renal tissue integrity. The redox status and oxalate metabolism in animals under oxalate overloading was also assessed. Microscopic analysis was done to investigate the abnormalities associated with oxalate exposure in renal tissues. Increase in oxidative milieu in hyperoxaluria was evident by increased lipid peroxidation (LPO) and decreased enzymic and nonenzymic antioxidants. Decrease in the activities of renal enzymes exemplified the damage induced by oxalate, which correlated positively with increased LPO and increased oxalate synthesis. Renal microscopic analysis further emphasized the oxalate-induced damage. These abnormal biochemical and histological aberrations were attenuated with test compound treatment, with 2 more effective than 1. From the present study, it can be concluded that 1 and 2 may serve as candidates for alleviating oxalate toxicity.

Effect of sulphated polysaccharides on erythrocyte changes due to oxidative and nitrosative stress in experimental hyperoxaluria

Kidney stones are known to haunt humanity for centuries and increase in oxalate is a predominant risk factor for stone formation. The present study was initiated with a notion to study the oxidative and nitrosative stress on erythrocytes under oxalate stress and the putative role of sulphated polysaccharides. Hyperoxaluria was induced in two groups by the administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with sulphated polysaccharides from Fucus vesiculosus from the 8th day to the end of the experimental period of 28 days at a dose of 5 mg/kg body weight subcutaneously. Control and drug control (sulphated polysaccharides alone) were also included in the study. Glycolic and glyoxylic acid levels of urine were analyzed as an index of hyperoxaluria. The plasma enzymic markers of cellular integrity, redox status of red blood cells, osmotic fragility, and 14C-oxalate binding were investigated. Urine and plasma nitric oxide metabolites, expression of inducible nitric oxide synthase protein, and mRNA were assessed in kidney to evaluate the nitrosative stress. Increased levels of glycolic and glyoxylic acid in urine indicated the prevalence of hyperoxaluria in ethylene glycol–administered groups. Plasma aspartate and alanine transaminase were not altered, but alkaline phosphatase and lactate dehydrogenase of hyperoxaluric group were increased indicating tissue damage. Activities of antioxidant enzymes were decreased, whereas erythrocyte membrane lipid peroxidation was increased in hyperoxaluric rats. Moreover, an altered fragility with an increase in oxalate binding activity was observed in hyperoxaluric group. Increase in nitric oxide metabolites levels in urine and plasma along with an increase in expression of inducible nitric oxide synthase protein and mRNA in kidney were observed in hyperoxaluric rats. Administration of sulphated polysaccharides to hyperoxaluric rats averted the abnormal increase in urinary glycolic and glyoxylic acid levels and enzyme activities, decreased lipid peroxidation, and increased the activities of antioxidant enzymes. Furthermore, increased nitrosative stress accompanying hyperoxaluria was also normalized on sulphated polysaccharides treatment. To conclude, sulphated polysaccharide administration was able to maintain the integrity of erythrocyte membrane and decrease the damage to erythrocytes in hyperoxaluria.

Physico‐chemical alterations of urine in experimental hyperoxaluria: a biochemical approach with fucoidan

Urinary supersaturation‐induced crystal formation has been attributed as one of the key factor for the pathogenesis/progression of lithogenesis. This study was aimed at investigating whether fucoidan, a naturally occurring sulfated glycosaminoglycan, could ameliorate the biochemical changes in urine induced by stone formation. Two groups of male albino Wistar rats (120 ± 20 g) received 0.75% ethylene glycol (EG) for 28 days to induce hyperoxaluria, and one of them received sulfated polysaccharides (fucoidan from Fucus vesiculosus, 5 mg kg−1, S.C.), commencing from the 8thday of the experimental period. One group was maintained as normal control group and another group served as drug control, which received sulfated polysaccharides. The urine collected from all the groups was analysed for changes in pH, volume, oxalate, calcium, phosphorus, uric acid, magnesium, citric acid and glycosaminoglycans. Urinary crystals were analysed with a light microscope. Renal tissues were studied under polarized light for deposition of crystals and also analysed for their oxalate and calcium content. The changes in extracellular matrix on crystal deposition were also evaluated. The urinary pH and volume were altered in rats treated with EG along with an increase in weight of the kidney. Further, administration of EG to rats increased the supersaturation of urine by escalating the levels of the stone‐forming constituents, such as oxalate, calcium, phosphorus and uric acid, which was completely restored by fucoidan treatment. The decrease in the inhibitors, like citrate, magnesium and glycosaminoglycans, in urine was prevented by the co‐treatment with fucoidan. In hyperoxaluric rats, there was an increased excretion of calcium oxalate monohydrate crystals in urine along with crystal deposition in renal tissues; this was prevented by fucoidan treatment. Fucoidan administration reversed even the tissue levels of calcium and oxalate. The increased accumulation of collagen and expression of transforming growth factor‐β1 in hyperoxaluria was normalized on fucoidan administration. These results suggest that the physico‐chemical alterations in urine produced during hyperoxaluria can be reversed by fucoidan administration.

Transcriptional repression mediated by 45-kDa calcium oxalate monohydrate binding protein

BackgroundThis study was done to investigate the DNA binding ability of a diagnostic biomarker, 45-kDa calcium oxalate monohydrate (COM) binding protein, isolated from human kidney and its effect on transcription.MethodsThe 45-kDa COM binding protein was isolated and purified from human kidney. The subcellular localization of the protein and the amino acid composition of the protein were analyzed. Oxalate-binding activity in the presence or absence of DNA was determined. The possibility of forming DNA-protein adducts was checked by diethylaminoethyl (DEAE)-Sephadex column chromatography. The effect of the protein on in vitro transcription was also studied.ResultsThe isolated 45-kDa protein was found to be basic in nature and its AACompIdent analysis showed it to be related to known transcription factors. The protein was found to be present in kidney cytosol and nucleus. The decreased oxalate binding activity in the presence of the DNA, and the shift in the DEAE-Sephadex elution profile established the DNA-binding ability of the protein. The in vitro transcription assay demonstrated the repression effect of the protein on gene expression during hyperoxaluria.ConclusionsTranscriptional repression by the 45-kDa COM binding protein in an in vitro transcription assay system was reduced in the presence of oxalate. Hence, altered expression of certain genes involved in the prognosis of urolithiasis might be mediated by this 45-kDa protein.