Artificial Perfusion of the Fetal Circulation of the In situ Mouse Placenta: Methodology and Validation

Here we present methodology and validation (including measurement of unidirectional maternofetal clearance (Kmf) of 45Ca and 14C-mannitol) for in situ perfusion of the mouse placenta. On day 18 of gestation (term = 19 days) mice were anaesthetised and the uterus delivered into a saline bath (40°C)....

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Veröffentlicht in:Placenta (Eastbourne) 2006-04, Vol.27, p.69-75
Hauptverfasser: Bond, H., Baker, B., Boyd, R.D.H., Cowley, E., Glazier, J.D., Jones, C.J.P., Sibley, C.P., Ward, B.S., Husain, S.M.
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Sprache:eng
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Zusammenfassung:Here we present methodology and validation (including measurement of unidirectional maternofetal clearance (Kmf) of 45Ca and 14C-mannitol) for in situ perfusion of the mouse placenta. On day 18 of gestation (term = 19 days) mice were anaesthetised and the uterus delivered into a saline bath (40°C). A fetus was selected, the umbilical artery and vein catheterised and perfused with Krebs Ringer (pH 7.4) at 60 μl/min. 45Ca/ 14C-mannitol (2 μCi/5 μCi in 50 μl saline) was injected via maternal tail vein. Perfusate samples were collected every 5 min for 45 min. Maternal carotid artery pressure was monitored throughout perfusion. A terminal maternal cardiac blood sample was taken and analysed. Placentas were immersion fixed and processed for electron microscopy. Kmf for 45Ca and 14C-mannitol was calculated as perfusate [ 45Ca or 14C-mannitol] × perfusion rate/maternal plasma [ 45Ca or 14C-mannitol] × placental weight. Maternal cardiac blood chemistry at termination ( n = 8–15, mean ± SEM) was as follows: pH 7.153 ± 0.016, PCO 2 45.48 ± 2.06 mmHg, PO 2 66.47 ± 7.10 mmHg, Na + 151.4 ± 1.2 mmol/l, K + 5.54 ± 0.17 mmol/l, Ca 2+ 1.15 ± 0.03 mmol/l, glucose 7.2 ± 0.5 mmol/l, and lactate 1.76 ± 0.77 mmol/l. A successful 45 min perfusion in which perfusate recovery was >95% occurred in >50% of animals. Perfusion did not alter placental morphology or carotid pressure. Kmf (μl/min/g placenta) for 45Ca (66.0 ± 8.4 ( n = 7)) was significantly higher than Kmf for 14C-mannitol (20.0 ± 2.4 ( n = 5)) ( p < 0.01). These data demonstrate physiological perfusion of the mouse placenta in situ and its usefulness for measurement of solute transfer.
ISSN:0143-4004
1532-3102
DOI:10.1016/j.placenta.2006.01.005