慢性肾病大鼠血管钙化与骨代谢标志物的相关性研究

目的研究慢性肾病(CKD)大鼠血管钙化与血清骨代谢标志物的相关性。方法将36只雄性SD大鼠随机分为对照组(18只)和CKD血管钙化组(18只)。钙化组予以腺嘌呤联合高磷饲料,对照组予以生理盐水和普通饲料。实验第2、4、6周末处死大鼠,留取主动脉行Von Kossa染色和钙含量检测钙化程度,留取血、尿检测尿素氮(BUN)、血肌酐(Scr)和骨代谢标志物:钙(Ca)、磷(P)、1,25-二羟基维生素D3(1,25(OH)2D3)、甲状旁腺素(PTH)、骨源性碱性磷酸酶(BALP)、骨钙素(OC)、总Ⅰ型前胶原氨基末端肽(tPINP)、β-Ⅰ型胶原交联羧基末端肽(β-CTX)、抗酒石酸酸性磷酸酶-5b(TRACP-5b)及24 h尿蛋白定量(24 h-Upro)。结果对照组各时间点主动脉Von Kossa染色均未见黑色物质沉积,CKD血管钙化组随时间进展黑色物质沉积逐渐增多。与对照组相比,CKD血管钙化组BUN、Scr、24 h-Upro、主动脉钙含量升高(P<0.05);Ca、1,25(OH)2D3、PTH、tPINP、β-CTX、TRACP-5b降低(P<0.05),P、Ca*P升高(P<0.05),BALP、OC升高(P>0.05);经二元logistic回归发现血清Ca*P升高、PTH和TRACP-5b降低是血管钙化的独立危险因素。根据主动脉钙化程度,将CKD血管钙化组进一步分为轻中度钙化(2 W和4W)和重度钙化(6 W)两个亚组。与轻中度钙化组相比,重度钙化组BUN、Scr、主动脉钙含量升高(P<0.05),24 h-Upro升高(P>0.05);Ca、P、1,25(OH)2D3、tPINP、TRACP-5b升高(P>0.05),Ca*P、PTH、BALP、β-CTX升高(P<0.05),OC降低(P<0.05);进行血管钙化严重程度的危险因素分析发现血清Ca*P升高和OC降低是血管钙化严重程度的独立危险因素。相关性分析显示血清Ca*P、PTH、BALP、β-CTX水平与血管钙化程度呈正相关,OC与血管钙化程度呈负相关。结论 CKD大鼠血管钙化与骨代谢密切相关,检测血清骨代谢标志物有助于评估血管钙化的发生和判断血管钙化的严重程度及进展。

Correlation between vascular calcification and bone metabolism markers in rats with chronic kidney disease

Objective To study the correlation between vascular calcification and serum bone metabolism markers in rats with chronic kidney disease.Methods Thirty six male SD rats were randomly divided into a control group(18 rats)and CKD vascular calcification group(18 rats).The calcification group was administered adenine combined with high phosphorus feed and the control group was administered normal saline and common feed.The rats were sacrificed after 2,4,and 6 weeks and the aorta was collected for Von Kossa staining and calcium content analysis to detect the degree of calcification.Blood and urine were collected to detect urea nitrogen(BUN),blood creatinine(Scr),and bone metabolism markers calcium(Ca),phosphorus(P),1,25-dihydroxy vitamin D3[1,25(OH)2D3],parathyroid hormone(PTH),bone alkaline phosphatase(BALP),osteocalcin(OC),total typeⅠprocollagen amino terminal peptide(tPINP),β-carboxy-terminal peptide of typeⅠcollagen(β-CTX),tartrate-resistant acid phosphatase-5 b(TRACP-5 b),and 24-hour urinary protein(24 h-Upro).Results Aortic Von Kossa staining showed no black matter deposition at each time point in the control group,whereas black matter deposition in the CKD vascular calcification group was increased gradually over time.Compared with the control group,the contents of BUN,Scr,24 h-upro,and aortic calcium were increased in the CKD vascular calcification group(P<0.05).Ca,1,25(OH)2D3,PTH,tPINP,β-CTX,and TRACP-5b were decreased(P<0.05),P and Ca*P were increased(P<0.05),and BALP and OC were also increased(P>0.05).Binary logistic regression showed that increased serum Ca*P and decreased PTH and TRACP-5 b were independent risk factors for vascular calcification.In accordance with the degree of aortic calcification,the CKD vascular calcification group was further divided into two subgroups:mild-moderate calcification(2 and 4 weeks)and severe calcification(6 weeks).Compared with the mild-moderate calcification group,the contents of BUN,Scr and,aorta calcium were increased in the severe calcification group,(P<0.05),while 24 h-upro was increased(P>0.05).Ca,P,1,25(OH)2D3,tPINP,and TRACP-5 b were also increased(P>0.05),while Ca*P,PTH,BALP,andβ-CTX were increased(P<0.05),and OC was decreased(P<0.05).Analysis of risk factors for the severity of vascular calcification revealed that increased serum Ca*P and decreased OC were independent risk factors for the severity of vascular calcification.Correlation analysis showed that serum Ca*P,PTH,BALP,andβ-CTX levels were positively correlated with vascular calcification,and OC was negatively correlated with vascular calcification.Conclusions Vascular calcification in CKD rats is closely related to bone metabolism.Detection of serum markers of bone metabolism is helpful to assess the occurrence of vascular calcification and judge the severity and progression of vascular calcification.