Calcium-sensing receptor promotes calcium oxalate crystal adhesion and renal injury in Wistar rats by promoting ROS production and subsequent regulation of PS ectropion, OPN, KIM-1, and ERK expression.

OBJECTIVES: To explore the mechanism of calcium-sensing receptors (CaSRs) during the development of nephrolithiasis. MATERIALS AND METHODS: Wistar rats were treated with ethylene glycol to induce calcium oxalate crystallization, and gadolinium chloride (GdCl3, an agonist of CaSR) and NPS 2390 (an antagonist of CaSR) were added. Oxidative stress (OS) and calcium oxalate crystals in the kidney were observed. CaSR expression and the expression of extracellular signal-regulated protein kinase (ERK), OPN, and KIM-1 were determined by western blotting. In addition, renal tubular epithelial cells were isolated from the kidney to observe phosphatidylserine (PS) ectropion using flow cytometric analysis. Various biochemical parameters were assessed in serum and urine at the end of the experiment. RESULTS: Calcium oxalate increased OS, crystal adhesion, PS ectropion, and the expression of CaSR and ERK, OPN, and KIM-1 in vivo. In addition, lower levels of urine citrate as well as increased serum creatinine and urea levels were observed after treatment with calcium oxalate (p < .05). Compared with calcium oxalate treatment alone, the above deleterious changes were further significantly confirmed by GdCl3 but were reversed by NPS-2390. However, urine calcium excretion was decreased after ethylene glycol treatment but was significantly reduced by NPS 2390 and increased by GdCl3 (p < .05). CONCLUSIONS: The results suggest that CaSR might play significant roles in the induction of nephrolithiasis in rats by regulating reactive oxygen species (ROS) and PS ectropion and the composition of urine, OPN, KIM-1, and ERK expression.

Structural characterization and antioxidant activity of a heteropolysaccharide isolated from Hedysarum polybotrys.

A water-soluble polysaccharide (HPS3aS) with a molecular mass of 1.22 × 10(4) Da was isolated from Hedysarum polybotrys using anion-exchange and gel-permeation chromatography. HPS3aS exhibits a globular-shaped conformation in 0.1 M NaNO3 by size exclusion chromatography with multi-angle laser light scattering (SEC-MALLS). The investigation of the structural features of this heteropolysaccharide through a combination of chemical and instrumental analyses revealed that the backbone of HPS3aS is composed of α-D-(1 → 4)-linked glucopyranose residues, which occasionally branched at O-6. The branches are composed of (1 → 4)-linked galactopyranose residues and terminated with glucopyranose residues. HPS3aS possesses good in vitro antioxidant activity, as evaluated by scavenging assays with 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and superoxide radicals, which suggests that HPS3aS could be a potential antioxidant.

Structure and antioxidant activity study of sulfated acetamido-polysaccharide from Radix Hedysari.

A new sulfated acetamido-heteropolysaccharide, HPS4-2A, was obtained by aqueous extraction followed by precipitation with ethanol and fractionation with DEAE column chromatography from Radix Hedysari. It was composed of rhamnose, arabinose, glucose, galactose and 2-acetamido-2-deoxy-d-galactose in the molar ratio of 10.09%:25.90%:25.90%:25.0%:12.30%. Elemental analysis indicated that HPS4-2A was a sulfated polysaccharide containing small amount of sulfate groups (1.87%). Partial acid hydrolysis, GC, GC-MS, 1D and 2D NMR spectroscopy analysis of the HPS4-2A revealed a predominance of glucose, galactose and 2-acetamido-2-deoxy-D-galactose linked in a highly-branched structure. The molecular weight of HPS4-2A was determined by HPSEC and HPSEC-MALLS. AFM study indicated that HPS4-2A took a highly branched conformation, which in consistent with the result studied by SEC-MALLS. Structural features of HPS4-2A were also investigated by SEM and TEM. Antioxidant assays demonstrated that HPS4-2A possessed of strong DPPH and hydroxyl radicals scavenging activities, suggesting that HPS4-2A could potentially be used as natural antioxidant.

[Spectrum-effect relationship in effect of improving immunity of astragali radix].

OBJECTIVE: To elaborate the correlation of chromatography fingerprint of Astragali Radix and the efficacy of improving immunity, and express the effective substances foundation. METHODS: The water extract was given to irrigation stomach of mice for carbon clearance experiment. Associated the peak area of each common peak from HPLC fingerprint and the date of improving immunity, and studied the correlation between fingerprint and efficacy and found out the effective substances foundation of improving immunity in the method of gray correlation analysis. RESULTS: Polysacharides was the main component of the water extract of Astragali Radix, which could improve immunity function. In carbon clearance experiment, the phagocytic index of the mice with water extract was the largest, and the ability to enhance immunity was the strongest. Grey correlation analysis was used to evaluate the correlation of the effect of improving immunity and the component of the water extract of Astragali Radix. CONCLUSION: It is effective to study the fingerprint and the correlation of fingerprint and the efficacy of traditional chinese medicine for expressing its correlation.