Effect of blood collection imitating toxicokinetic study on rat hematological parameters

The effect of blood collection imitating a one-month toxicokinetic study on hematological parameters was studied in male rats (6 weeks of age at the beginning of the experiment). Three groups were established according to blood sampling points per day; Group I (3 points), Group II (5 points) and Group III (10 points). These repeated blood samplings were carried out on the first and last days of this study, and one-point blood sampling was also done every week during the experiment. In each sampling, 0.3 ml of blood was collected from the jugular vein. There were no changes in Group I, but in other groups, especially in Group III, red blood cell counts, hematocrit and hemoglobin concentration decreased during repeated blood sampling. On the other hand, white blood cell counts also decreased, but recovered within 24 hr. Platelet counts did not show any decrement. From the present result, less than 0.9 ml of blood per day is conceivable as the volume without causing changes in hematological parameters. The baseline of the sampling volume can become one reference for toxicokinetic and toxicological studies.