OBJECTIVETo observe the changes of urinary deoxypyridinoline crosslink/creatinine (UDpd/Cr) in rats after OVX and intervention by estrogen and bisphosphonate and investigate the possible application of deoxypyridinoline in osteoporosis diagnosis and treatment.

METHODS40 female 6-month-old virginal Wistar rats were divided into 5 groups, ovariectomized or sham ovariectomized. (1) Ovxb (n = 8): sacrificed at 6 weeks after OVX; (2) Sham (n = 8): sham ovariectomized; (3) Ovxe (n = 8): sacrificed at 14 weeks after OVX; (4) O + E (n = 9):OVX + 17 beta estradiol [20 micrograms/(kg.d) ih]; (5) O + C (n = 7):OVX + cimadronate [0.2 mg/(kg.d)]; Treatment started 6 weeks after OVX and lasted 8 weeks. Rats in group 2-5 were sacrificed at 14 weeks after OVX. Urinary and serum biochemical parameters were measured, pQCT scanning of femur, bone biomechanical test in femur were determined.

RESULTSOVX resulted in increasing of UDpd/Cr 133.3% (P < 0.01). The ratio of UCa/Cr also increased in OVX groups but without any significant compared with Sham (P > 0.05). UDpd/Cr were reduced by 54.6% and 51.8% (P < 0.01) in O + E, O + C group respectively compared with Ovxe. The significant negative correlationships were found between UDpd/Cr and bone mass, BMD and biomechanic characteristics.

CONCLUSIONSUDpd/Cr ratio is a sensitive bone resorption marker, a marked changes were observed when the rats ovariectomized or treated with estradiol and cimadronate. There were best correlation between UDpd/Cr and bone mineral density and bone biomechanic characteristics. It is fair to apply UDpd/Cr ratio for osteoporosis diagnosis and treatment.