Comparison of inferior vena cava puncture under continuous cardiac perfusion with cardiac puncture in blood acquisition of the laboratory mouse

Obtaining sufficient blood volume from mice significantly facilitates experimental research. This study explored the inferior vena cava puncture under continuous cardiac perfusion (IVCP-UCCP) technique and evaluated its efficiency in comparison with conventional cardiac puncture (CP). In an initial dose-finding study, 50 mice were randomly assigned to one of 10 groups with escalating perfusion volume from 0.5 to 4.5 ml in 0.5-ml increments. The minimum perfusion volume was determined to be 2 ml in collecting whole circulating blood. In the next comparison using the conventional method, 40 mice were randomly assigned to one of two groups denoting different blood collection methods: Group 1: CP, Group 2: IVCP-UCCP. The results showed 1) that the cells and undiluted blood volume collected via IVCP-UCCP was over twofold higher than that by CP (p < 0.001), confirmed by the cell counts and hematoxylin-eosin staining of different tissues slides (p < 0.001); 2) the new technique did not alter the cellular composition or viability, which was verified by routine blood tests and flow cytometry (p > 0.05); 3) the blood collected via the novel technique was diluted 2.1 times: the hemato-biochemical indicator results multiplied by 2.1 were identical with the test results of blood from CP (p > 0.05). Together, the refined blood collection method of IVCP-UCCP completely extracted the limited blood resources in mice, significantly enhanced the utilization of each mouse, and thus offered scientific and ethical benefits. This technique may be also applicable for other small animal models.