Study On The Role Of Vascular Calcification Related Regulatory Factors In The Pathogenesis Of Uric Acid Nephropathy

Objective To study the relationship between uric acid and renal calcification,the regulating effect of Cbf?1?TNF-??OPN and OPG on calcification,and the effect of calcium antagonist on the calcification and calcification regulating factors through investigating the experimental models;To explore the mechanism of calcification in renal tissue of uric acid nephropathy.Methods1.45 male Wistar rats were randomly divided into three groups:norm group,model group and amlodipine group.The rats were fed with 10% yeast diet,and administered intragastrically with adenine(100mg/kg.d)for modeling.amlodipine(10mg/kg.d)was alse given orally to evaluate their effect on experimental uric acid nephropathy.All the rats were killed after four weeks.2.The rats angular venous blood and urine was collected for detecting uric acid(UA),creatinine(SCr),urea nitrogen(BUN)and 24 hour urine microalbuminuria.3.The right kidneys were obtained after executed and half of renal tissue was used to study renal histological changes by Haematoxylin & eosin(HE)and the Calcium content of Renal tissue,and the expression of Cbf?1?TNF-??OPN and OPG were analyzed by immunohistochemical staining.4.Half of renal tissue was used to study the protein expression of Cbf?1 ?TNF-??OPN and OPG were analyzed by Western Blot and the gene expression of Cbf?1 ?TNF-? ?OPN and OPG were analyzed by reverse transcription-PCR.Results1.Compared with normal group,model group and amlodipine group after 4weeks showed much higher UA?SCr?BUN and 24 hour urine microalbuminuria(P<0.05).There was no significant difference in the levels of UA?SCr?BUN and 24 hour urine microalbuminuria between model group and amlodipine group(P>0.05).Renal pathological tissue in model group showed the renal tubules were dilated and edematous,the epithelial cells of the tubule were moderately damaged and the tubulointerstitium was infiltrated by inflammatory cells.2.Compared with normal group,model group and amlodipine group after 4weeks showed much higher calcium contents in Renal tissue(P<0.01),and amlodipine group showed significantly lower calcium contents in Renal tissue than model group(P<0.01).3.Compared with normal group,model group and amlodipine group showed much more renal deposition and Cbf?1 ?TNF-??OPN and OPG expression(P<0.01).Compared with model group,amlodipine group showed significantly lower Cbf?1 ?TNF-??OPN and OPG expression,and renal deposition by immunohistochemical staining(P<0.01).The four regulatory factors were expressed in renal tubules in three groups.4.Compared with normal group,model group showed much more protein expression of vascular calcification promotion factors(Cbf?1 ? TNF-?)and vascular calcification suppressors(OPN? OPG)(P<0.01).Compared with model group,amlodipine group showed significantly lower Cbf?1 ?TNF-??OPN and OPG protein expression in renal tissue by Western Blot(P<0.01).There was no significant difference in the levels of the four regulatory factors between normal group and amlodipine group(P>0.05).5.Compared with normal group,model group showed much more m RNA expression of vascular calcification promotion factors(Cbf?1 ? TNF-?)and vascular calcification suppressors(OPN?OPG)(P<0.01),and amlodipine group showed much more m RNA expression of vascular calcification suppressors(OPN? OPG)(P<0.01).Compared with model group,amlodipine group showed significantly lower Cbf?1(P<0.01)?TNF-?(P<0.05)?OPN(P<0.01)and OPG(P<0.01)m RNA expression in renal tissue by Real-time RT-PCR.There was no significant difference in Cbf?1 and TNF-? m RNA expression between normal group and amlodipine group(P>0.05).Conclusion1.Our study showed that Hyperuricemia could increase the calcium content in renal tissue of rats with uric acid nephropathy and the protein and m RNA expression in renal tissue vascular calcification promotion factors(Cbf?1?TNF-?)and vascular calcification suppressors(OPN? OPG).2.amlodipine could reduce the calcium content in renal tissue of rats with uric acid nephropathy and the protein and m RNA expression in renal tissue vascular calcification promotion factors(Cbf?1 ? TNF-?)and vascular calcification suppressors(OPN? OPG).3.It was inferred that imbalances between vascular calcification promotion factors(Cbf?1?TNF-?)and suppressors(OPN? OPG)may be involved in the pathogenesis of uric acid nephropathy.