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

Abstract

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 8(th) day 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-beta(1) 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.

Fucoidan: Structure and Bioactivity

“…Fucoidan administration was able to maintain the integrity of erythrocyte membrane and decrease the damage to erythrocytes in hyperoxaluria [ 124 ]. Advocation of fucoidan enhanced the antioxidant status, thereby preventing membrane injury and alleviating the microenvironment favorable for stone formation [ 125 ]. Urinary supersaturation-induced crystal formation has been attributed as one of the key factor for the pathogenesis/progression of lithogenesis.…”

Marine Polysaccharides from Algae with Potential Biomedical Applications

“…Being an antioxidant against free radicals, fucoidan from F. vesiculosus might be an alternative or complementary therapeutic in uropathy and renalpathy, since it could prevent from the injuries caused by oxalate-induced free radicals [ 362 ] and from the mitochondrial damages associated to the process [ 363 ]. Several other disorders of the urinary system, including Heymann nephritis, are also liable to treatment or complementary therapeutics through the use of fucoidans [ 293 , 364 , 365 , 366 , 367 ].…”

Recent Advances on Bioactivity of Seaweed Polysaccharides

“…[48] These anions increase the concentration of soluble Ca 2+ in the supernatant and reduce the degree of supersaturation of the renal fluid, thereby inhibiting the nucleation of CaOx crystals ( Figure 5). [49] Veena et al [50] found that Fucoidan, extracted from Fucus, reduced the content of major components of kidney stones, such as calcium, oxalate, uric acid, and phosphorus in urine. Figure 5 he sequential schematic for the inhibitory mechanism of seaweed polysaccharides at each step of CaOx stone formation.…”