The Expression Of Runx2 And Co1Ⅱ In Vascular Calcification Of Remnant Kidney Rat With Hyperphosphatemia

[Objective]This study is aimed to observe the expression of Runx2 and Colâ…¡involved in vasucular calcification in remnant kidney rats with hyperphosphatemia; and to explore the mechanisms of vascular calcification of chronic renal failure.[Methods]1. Sprague Dawley rats (n=40) underwent 5/6 nephrectomy (n=20) or sham operation (n=20). After 5/6 nephrectomy, forty rats were fed with high phosphorous (HP) diet [diet formular: phosphate (P) 1.2%, calcium (Ca) 1.6%] or normal phosphorous (NP) diet [diet formular: P (0.9%), Ca (1.2%)] for 16weeks respectively. They were divided into 4 groups as follows: (1) remnant kidney rats receiving HP diet( n=10 ) (2) remnant kidney rats receiving NP diet( n=10 ), (3) sham operation rats receiving NP diet( n=10 ), (4) sham operation rats receiving HP diet( n=10 ). At the 16th week (end point), serum creatinine (Scr), urea nitrogen (UN), serum P, LDL were examined,.. At the 16th week, throacic aorta was removed. Calcification was confirmed by von kossa staining.Runx2 mRNA and Colâ…¡mRNA were determined by RT-PCR, Runx2 expression was determined by immunohistochemistry and Western Blot, Colâ…¡expression was determined by immunohistochemistry.[Results]1. After 16 weeks, serum urea nitrogen, creatinine levels were significantly higher in 5/6 nephrectomy rats than those in sham nephrectomy operation rats. (P< 0.05 ) . Serum P level increased significantly in remnant kidney rats receiving HP diet, compared three other groups. (P< 0.05 ) .2. After 16 weeks, von kossa staining showed that significant vascular calcification was found in remnant kidney rats receiving HP diet while the remnant kidney rats receiving NP diet and sham nephrectomy operation rats receiving HP diet occasionally had vascular calcification, sham nephrectomy operation rats receiving NP diet had no vascular calcification.3. The expression of Runx2, Colâ…¡increased signicificantly in remnant kidney rats receiving HP diet, compared with three other groups by immunohistochemistry (P<0.05). Serum P was positively correlated with Runx2(r= 0.525,P<0.05),and Colâ…¡(r=0.640,P<0.05)respectively.4. The expression of Runx2 mRNA, increased significantly in remnant kidney rats receiving HP diet compared with three other groups by RT-PCR (P<0.05). While Colâ…¡mRNA increased significantly in remnant kidney rats compared with sham nephrectomy operation rats by RT-PCR (P<0.05 ).5. The expression of Runx2 increased signicificantly in remnant kidney rats receiving HP diet, compared with three other groups by Western Blot ( P<0.05).[Conclusion]1. The morpholgy of vascular calcification in remnant kidney rat with hyperphosphatemia approximate to chronic renal failure patient, so it may serve as a useful model for vascular calcification of chronic renal failure.2. Hyperphosphatemia may be an important factor to influence vascular calcification. Serum P was positively correlated with Runx2 and Colâ…¡respectively3. The higher expression of Runx2 and Colâ…¡may be involved in vascular calcification of remnant kidney rat...