Unique Features

  • Derived exclusively from bone-resorbing osteoclasts
  • Low diurnal variation
  • No dietary influences
  • No accumulation into the circulation in renal or hepatic failure
  • Only bone resorption marker useful in renal research and for non-fasting samples
  • A complete assay panel supporting bone research

The MouseTRAP (TRAcP 5b) ELISA test is a solid phase immunofixed enzyme activity assay for the determination of mouse tartrate-resistant acid phosphatase form 5b (TRACP 5b).

The MouseTRAP (TRAcP 5b) ELISA assay can also be used in in-vitro mouse osteoclast cultures to measure TRACP 5b activity from cell lysates or culture medium. Because secreted TRACP 5b indicates the number of osteoclasts, TRACP 5b values determined from mouse osteoclast culture medium can be used to replace microscopic counting of the number of osteoclasts, and serum TRACP 5b values can be used to replace histological determination of osteoclast number in mouse bone.

High amounts of tartrate-resistant acid phosphatase (TRACP) are expressed by bone-resorbing osteoclasts and
activated macrophages. Two forms of TRACP circulate in blood, known as TRACP 5a and TRACP 5b. TRACP 5b is derived from osteoclasts and TRACP 5a from inflammatory macrophages. Osteoclasts secrete TRACP 5b into the blood circulation as an active enzyme that is inactivated and degraded to fragments before it is removed from the circulation. Thus, TRACP 5b activity does not accumulate into the circulation in renal or hepatic failure.

Diurnal variability of serum TRACP 5b is low and the levels are not affected by feeding, allowing sample collection at any time of day. Recent studies have shown that secreted TRACP 5b indicates the number of osteoclasts rather than their activity.

Thudium CS et al., A comparison of osteoclast-rich and osteoclast-poor osteopetrosis in adult mice sheds light on the role of the osteoclast in coupling bone resorption and bone formation. Calcif Tissue Int. 2014 Jul;95(1):83-93.

Linares GR et al., Claudin 18 is a novel negative regulator of bone resorption and osteoclast differentiation.

Li X et al., Drugs which inhibit osteoclast function suppress tumour growth through calcium reduction in bone.