Abstract:The structure-activity relationships and repair mechanism of six low-molecular-weight seaweed polysaccharides (SPSs) on oxalate-induced damaged human kidney proximal tubular epithelial cells (HK-2) were investigated. These SPSs included Laminaria japonica polysaccharide, degraded Porphyra yezoensis polysaccharide, degraded Gracilaria lemaneiformis polysaccharide, degraded Sargassum fusiforme polysaccharide, Eucheuma gelatinae polysaccharide, and degraded Undaria pinnatifida polysaccharide. These SPSs have a narrow difference of molecular weight (from 1968 to 4020 Da) after degradation by controlling H 2 O 2 concentration. The sulfate group (-SO 3 H) content of the six SPSs was 21.7%, 17.9%, 13.3%, 8.2%, 7.0%, and 5.5%, respectively, and the -COOH contents varied between 1.0% to 1.7%. After degradation, no significant difference was observed in the contents of characteristic -SO 3 H and -COOH groups of polysaccharides. The repair effect of polysaccharides was determined using cell-viability test by CCK-8 assay and cell-morphology test by hematoxylin-eosin staining. The results revealed that these SPSs within 0.1-100 µg/mL did not express cytotoxicity in HK-2 cells, and each polysaccharide had a repair effect on oxalate-induced damaged HK-2 cells. Simultaneously, the content of polysaccharide -SO 3 H was positively correlated with repair ability. Furthermore, the low-molecular-weight degraded polysaccharides showed better repair activity on damaged HK-2 cells than their undegraded counterpart. Our results can provide reference for inhibiting the formation of kidney stones and for developing original anti-stone polysaccharide drugs.

Abstract:Purpose: This research aims to study the influences of heparin (HP) on the aggregation of nano calcium oxalate monohydrate (COM) and nano calcium oxalate dihydrate (COD) with mean diameter of about 50 nm. Method: The influences of different concentrations of HP on the mean diameter and Zeta potential of nano COM and nano COD were investigated using a nanoparticle size Zeta potential analyzer. Results: HP could be adsorbed on the surface of nano COM and nano COD crystals, leading to an increase in the absolute value of Zeta potential on the crystals and an increase in the electrostatic repulsion force between crystals. Consequently, the aggregation of the crystals is reduced and the stability of the system is improved. The strong adsorption ability of HP was closely related to the -OSO3 − and -COO − groups contained in the HP molecules. X-ray photoelectron spectroscopy confirmed the coordination of HP with Ca 2+ ions of COM and COD crystals. Conclusion: HP could inhibit the aggregation of nano COM and nano COD crystals and increase their stability in aqueous solution, which is conducive in inhibiting the formation of calcium oxalate stones.

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The main components of urinary crystallites in patients with CaOx stones were calcium oxalate monohydrate (COM), uric acid (UA), calcium oxalate dihydrate (COD) and calcium phosphate (CaP), which were similar to the components of stones (COM, COD, UA, and CaP).[Conclusions] The formation of CaOx stone was related to the presence of COM, UA, and CaP crystals in urine. UA and CaP crystals could induce the development of CaOx stones by heterogeneous nucleation. The formation mechanism and the influential factors of CaOx stones were discussed on the basis of the components of urinary crystallites.