Abstract
In measuring the activities of blood coagulation factors in rats, the method for the human clinical examination has been applied. However, the values would be off the scale and inappropriate assessment has been made as the human method is directly employed. In this study, we have investigated the linearity of coagulation factors (Factor II, V, VII, VIII, IX, X, XI and XII) and explored the appropriate dilution factor of rat sample. The blood was collected into a tube containing 3.8% sodium citrate at a ratio of 1:9 anticoagulant blood from Wistar/SD rats. ACL Elite Pro (Instrumentation Lab) was used as the analyzer. We revealed the measurement range of all coagulation factors tested in which the activities maintained linearity. On the basis of these results, we propose the suitable dilution factor about 3 to 4 for II, IX, X, XI and XII, about 4 to 8 for V and VIII, and about 20 for VII. Whereas, it was also noted that vitamin K-dependent factors were decreased by fasting in male SD rats. This means necessity to apply lower dilution factors to fasted male SD rats than non-fasted ones, i.e., dilution factor 1 (no dilution) for II, IX, and X, and 3 for VII. In the toxicity study, coagulation time is commonly prolonged by the effect of test article. In such cases, the dilution should be arranged low as in the fasted rats. Applying the human method to animals, sample dilution factors should be adjusted properly in consideration of species, fasting and test article. This study become a baseline in measuring coagulation factor activities in rats.
