ABSTRACT
OBJECTIVE：To discuss the inhibitory effect of lanthanum chloride on the calcification of vascular smooth muscle cells（VSMCs）induced by high phosphorus and its mechanism. METHODS ：On the basis of screening the action concentration and time of lanthanum chloride by MTT method ，human VSMCs were divided into control group （1 mmol/L phosphorus solution ）， lanthanum chloride high concentration control group （1 mmol/L phosphorus solution+ 60 μmol/L lanthanum chloride），model group （3 mmol/L phosphorus solution ），sodium chloride group （3 mmol/L phosphorus solution+ 180 μmol/L sodium chloride），nuclear factor κB（NF-κB）signaling pathway agonist+lanthanum chloride group （3 mmol/L phosphorus solution+ 1 μg/mL lipopolysaccharide+ 60 μmol/L lanthanum chloride），positive control group （3 mmol/L phosphorus solution+ 100 μmol/L sodium pyrophosphate），and lanthanum chloride low ，medium，and high concentration groups （3 mmol/L phosphorus solution+ 15，30，60 μmol/L lanthanum chloride）. Alizarin red S staining and Von Kossa staining were used to detect cell calcification in each group after treated with phosphorus solution for 6 d and relevant medicine for 2 d. Western blot assay was used to detect the protein expression of TNF-α receptor associated protein 6（TRAF6），nuclear factor κB inhibitor protein α（IκBα），NF-κB p65，bone morphogenetic protein 2 （BMP-2），smooth muscle 22 α（SM22α）and Runt related transcription factor 2（Runx2）. Real-time fluorescence quantitative polymerase chain reaction was used to detect mRNA expression of TRAF 6，IκBα，BMP-2，SM22α and Runx2. RESULTS ： Compared with control group ，no cell calcification was observed in the lanthanum chloride high concentration control group ，while obvious cell calcification and significant increase of OD value were observed in model group and sodium chloride group （P＜ 0.01）；protein and mRNA expression of TRAF 6 and BMP- 2 in cytoplasm as well as mRNA expression of Runx 2，protein expression of NF-κB p65 and Runx 2 in nucleus were significantly increased （P＜0.01）；protein and mRNA expression of IκBα and SM22α as well as protein expression of NF-κB p65 in cytoplasm were significantly decreased （P＜0.01）. Compared with model group，cell calcification was significantly improved in lanthanum chloride groups and positive control group ，while OD values were significantly reduced ；the expression levels of the above-mentioned protein and mRNA were reversed to varying degrees （P＜0.05 or P＜0.01）. Compared with lanthanum chloride high concentration group ，obvious cell calcification was observed in NF-κB signaling pathway agonist + lanthanum chloride group ，and OD value was significantly increased ；the above indexes were significantly reversed in cytoplasm and nucleus （P＜0.05 or P＜0.01）. CONCLUSIONS ：Lanthanum chloride can inhibit the calcification of VSMCs induced by high phosphorus ，and its mechanism may be related to the inhibition of NF-κB signaling pathway activation.
ABSTRACT
The extensive use of food additives has increased the phosphorous content of the modern diet, while calcium intake has remained similar to past levels according to the national standards of nutrient intake. Although exercise increase bone mineral content, the intake of phosphorus may change the exercise effect. The purpose of this study was to examine the effects of jump exercise on bone and phosphate-calcium metabolism in rats consuming high levels of dietary phosphorous. Forty-two male Wistar rats aged 8 weeks were fed either a high-phosphorus diet with a 2.0 P/Ca ratio or a normal diet with a 1.0 P/Ca ratio. Rats from each dietary group were then further assigned to undergo 8 weeks of jump exercise or to be sedentary controls. Two-way analysis of variance (ANOVA) revealed that the bone mineral content (P<0.001), strength (P<0.001), transverse thickness (P<0.001), and longitudinal thickness (P<0.001) of the tibial diaphysis were increased by jump exercise in both dietary groups. The concentrations of serum inorganic phosphorus (P<0.001), FGF23 (P<0.001), and 1-25 (OH) vitamin D (P<0.001) were increased by a high phosphorus diet, and the concentrations of serum total calcium (P<0.05) and 1-25 (OH) vitamin D (P<0.05) were increased by jump exercise in both groups. In conclusion, exercise is important to increase bone mass and bone strength in a high phosphorus intake state.
ABSTRACT
Objective:To establish a rat hyperparathyroidism model secondary to chronic renal failure,so as to lay a foundation for studying the mechanism and treatment of secondary hyperparathyroidism.Methods: Thiry-six male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 6 groups: 5/6 nephrectomy plus high phosphorus food group(STNx + HP),5/6 nephrectomy plus low phosphorus food group(STNx + LP),5/6 nephrectomy plus normal phosphorus food group(STNx + NP),sham operation plus high phosphorus food group(Sham + HP),sham operation plus low phosphorus food group(Sham + LP),and sham operation plus normal phosphorus food group(Sham + NP).Nephrectomy was performed in 2 steps.Serum phosphorus levels(P) and iPTH levels were detected at day 7 pre-operation and day 7,14,and 21 after the second operation.The kidneys,thyroid glands and parathyroid glands complex underwent pathological analysis 4 weeks after operation.Results: Five patients survived in STNx+NP group,4 in STNx+LP group and 4 in STNx+HP group postoperatively.No death occurred in sham operated groups.Serum phosphorus levels of nephrectomy groups at different time points after operation were higher than those before operation and those of sham operation groups(P