Temporal response of ovine fetal plasma erythropoietin induced by fetal hemorrhage

Kim, Sa Jin; Brace, Robert A; Lee, Gui Se Ra; Rho, Seung Hye; Shin, Jong Chul; Jung, Dae Young; Yi, Young; Kim, Jin Woo; Kim, Soo Pyoung

Abstract

OBJECTIVE
The ovine fetus responds to hemorrhage with a 10-20 fold increase in plasma erythropoietin (EPO) concentration at 24 hr and a return toward normal at 48 hr after the hemorrhage. The objective of the present study was more accurately to compare the magnitude and time course of the plasma EPO response after fetal hemorrhage. METHODS: Chronically catheterized, 12 of late gestation ovine fetus were gradually hemorrhaged 40% of their blood volume over 2 hr (1ml/min). Plasma was sampled for EPO concentration at 1, 2, 3, 4, 6, 8, 10, 12, 16, 20, 24, 30, 36 hr after initiating the hemorrhage were collected at these times. Radioimmunoassay was used to measure plasma EPO concentrations. Analysis of variance was used for statistical analysis. RESULT: After a slow hemorrhage in the ovine fetus (1ml/min over 2hr), plasma EPO concentration increased significantly at 4hr (2.3 times basal values), reached a maximum at 16 hr (33.3 times basal values), and declined thereafter. CONCLUSION: We studied change in time course of the fetal plasma EPO after slow hemorrhage and recent studies have shown that the fetal kidney, liver and placenta express EPO mRNA. These observation suggest that plasma EPO increase may be mediated by a tissue specific up-regulation of EPO transcription in the fetal kidney, liver and placenta. We have studied change in Epo mRNA expression in various fetal tissue after slow haemorrhage.