PARENT SESSION
NUCLEAR TRANSFER, CLONING, AND REPRODUCTIVE TECHNOLOGIES
Harborside C
7:30 AM-10:00 AM

(339) EXPRESSION OF VASCULAR ENDOTHELIAL GROWTH FACTOR mRNA IN BOVINE PLACENTAS FROM EMBRYOS PRODUCED IN VIVO OR IN VITRO.

Miles, Jeremy¹, Farin, Charlotte², Stockburger, Elaine¹, Rodriguez, Karina², Alexander, Joseph², Farin, Peter¹, ¹ Department of Farm Animal Health and Resource Management, Raleigh, NC² Department of Animal Science, Raleigh, NC

ABSTRACT- The transfer of embryos produced in vitro can result in fetuses with increased body weight and placental abnormalities, commonly termed large offspring syndrome. The role of the placenta in this syndrome is poorly understood. The purpose of this study was to determine the effect of in vitro embryo culture on vascular development of the placenta as assessed by expression of vascular endothelial growth factor (VEGF) mRNA during late gestation. In vivo embryos were recovered from superovulated Holstein cows (multiple ovulation, MO). In vitro embryos were produced using a serum-containing culture system (IVPS). Single blastocysts from each production system were transferred non-surgically into heifers. On Day 222 of gestation, fetuses and placentas were recovered in utero (MO, n=12; IVPS, n=12). Samples of cotyledonary tissue were obtained for quantification of VEGF mRNA. Sequence specific primers were designed to amplify a 115-bp fragment of VEGF mRNA. The resulting PCR product was verified by sequence analysis. These primers were used for quantification of VEGF mRNA levels by real-time quantitative reverse transcription PCR using a SYBR Green detection system. Data were analyzed by General Linear Models procedures. Fetuses from the IVPS group were heavier (P=0.03) than those from the MO group (17.3±1.0 kg and 20.7±1.0 kg for MO and IVPS, respectively; LS means ± SEM). Placentas were also heavier (P=0.06) for the IVPS group (2.5±0.2 kg) compared to the MO group (1.9±0.2 kg). Feto-maternal contact area, as measured by the percent caruncular surface area, was less (P=0.002) for the IVPS group (57.2±2.5%) compared to the MO group (70.2±2.5%). However, the levels of VEGF mRNA were increased (P=0.01) in cotyledonary tissue for the IVPS group (22.6±0.1 relative units) compared to the MO group (22.0±0.1 relative units). In summary, compared to placentas from embryos produced in vivo, placentas from embryos produced in vitro had decreased feto-maternal contact area and increased expression of VEGF mRNA in cotyledonary tissues. Supported by the State of North Carolina, and USDA Grant 9602482

KEY WORDS: In vitro embryo production, Bovine, Placenta, VEGF mRNA