Abstract: Objective To observe the physiological and pathological characteristics of forelimb and serum calcium (Ca) and phosphorus (P) levels in forelimb malformed white hair and black eyes (FMWHBE) rabbits, to discuss the possible causes of forelimb malformation in white hair& black eyes (WHBE) rabbits, and to evaluate possibility of FMWHBE rabbit as a potential model in bone biomechanics research such as spontaneous osteoporosis animal model. Method Totally 1, 2, 3 and 4 months old FMWHBE rabbits, WHBE rabbits and Japan white (JPW) rabbits were used respectively (6 rabbits in each group, totally 72 rabbits).The levels of serum Ca, P and alkaline phosphatase (ALP) were tested in all rabbits. The bone mineral density (BMD) of fore humerus, radius and ulna were measured by using X-ray imaging system. Pathologic analysis was performed by H&E staining. Results Compared with JWP rabbits, the serum Ca content of 1, 2 and 4 months old FMWHBE rabbits was significantly lower (P<0.05 or P<0.01). The serum P content of 4 months old FMWHBE rabbits was significantly higher than JPW rabbits at the same age(P<0.05 or P<0.01). The serum ALP levels of FMWHBE rabbits was significantly lower than JPW rabbits and WHBE rabbit (P<0.05 or P<0.01). Compared with the same period WHBE rabbit, the BMD of fore humerus of 1-4 month old FMWHBE rabbit , radial of 2, 3, 4-month-old rabbit and ulna of 2-month-old FMWHBE rabbit were significantly lower (P<0.05 or P<0.01). Compared with the same period JPW rabbits , the BMD of fore humeral and radius of 1, 3 months old rabbits, the ulna of 1, 2-month old rabbits were significantly lower (P<0.05 or P<0.01). Compared with WHBE and JPW rabbits, the cortex of fore humerus, radius and ulna in FMWHBE rabbits was thinner. There were less osteoblasts on local bone tissue surface and none of them were arranged in a layer trimly. Bone canalicules and new bone tissue were less. Conclusion The malformation of FMWHBE rabbits may be related with the low levels of Ca and P in blood leading the loss of osteoblasts and new bone tissue.

Key words: Forelimb malformed white hair& black eyes (FMWHBE) rabbits, Bone mineral density (BMD), Calcium(Ca), Phosphorus(P), Alkaline Phosphatase(ALP)