The effects of calbindin-D28k on mice skeletal growth / 中国医师杂志

ABSTRACT

Objective To investigate the role of Catbindin-D28k in the kidney on calcium metabolism.Methods VDR/CaBP-D28k double knockout(KO)mice was made.Body weight,diet intake and serum,urinary parameters and length,density of the long bones,histological staining of the tibia of WT,CaBP-D28(-/-),VDR(-/-)and VDR(-/-)/CaBP-D28k(-/-)mice were determined on regular and high Ca-Lac diet.Results On a regular diet,the double KO mice were growth-retarded more and smaller than VDR KO mice.Compared with VDR KO mice,the double KO mice had higher urinary calcium excretion and rachitic skeletal phenotype,which were manifested with higher serum parathyroid hormone levels,lower bone mineral density,and more distorted growth plate with mole osteoid formation in the trabecular region.On high calcium and high lactose diet,blood-ionized calcium levels were normal in both VDR KO and the double KO mice.However,in contrast to VDR KO mice,the skeletal abnormalities were not completely corrected in the double KO mice.Conclusion These results directly demonstrate that CaBP-D28k plays a critical role in maintaining calcium homeostasis and skeletal mineralization and suggest that its caleemic role can be mostly compensated by CaBP-D9k.