Technical Report: Mouse Fetal Blood Collection Taking the Best out of the Old Needle-Syringe Method

Abstract

Collection of mice blood is not a common practice due to technical difficulties and the small volumes collected. This constrains many researchers that often choose indirect types of sampling to follow fetal and gestational development, diagnosis and therapy. This study is part of wider studies, in which the above technique was optimized in order to obtain larger volumes.

Timed-pregnant ICR (CD-1®) mice were used. After anesthesia fetuses were rapidly delivered by hysterectomy at gestational days 15, 16, 17 and 18. Large vessels in the fetuses thorax were cut, and blood was collected using several different techniques: a) capillary tubes, b) Microvette® CB 300 (Sarstedt), c) micropipetes, d) different gauge needles and syringe, and e) a hand-modified 20G needle applied to a 1ml/100 IU syringe.

The volumes obtained with the modified 20G needle at 15, 16, 17 and 18 gestational days ranged respectively from: 30 to 45, 50 to 70, 80 to 100, and 120 to 140 μl. The optimization of this technique allows the measurement of biochemical parameters during fetal development and may help to reduce the number of animals used for similar procedures.