Coagulation phenotype of wild-type mice on different genetic backgrounds:

Genetically engineered mouse models are used to investigate beneficial treatment in haemophilia by comparison with wild-type mice. It has been recognized that wild-type and haemophilic mice of different genetic backgrounds show different bleeding phenotypes. We assessed ex-vivo coagulation parameters in nine wild-type substrains of 129S1/Sv, BALB/c and C57BL/6 mice applying thromboelastography (TEG), activated partial thromboplastin time (aPTT), prothrombin time (PT) and fibrinogen levels. The comprehensive ex-vivo data are discussed in view of results from a tail-tip bleeding assay. Time to first clot formation (R-time) showed higher within-substrain (CV range: 28–54%) and higher between-substrain (median range: 25.53–42.60 min) variation for BALB/c than for C57BL/6 mice (CV range: 14–31%; median range: 22.45–24.93 min). Median R-time for 129S1/Sv mice was 30.42 min (CV: 33%). No distinct strain differences were observed for maximum amplitude (MA), aPTT, or PT, but males generally showed higher MA and sh...