Reciprocal Embryo Transfer Between Spontaneously Hypertensive and Normotensive Rat Strains: I. Reproductive Characteristics and Transfer Technique

Abstract

The conditions necessary to achieve successful transfer and development of embryos between two separate genetic lines of Wistar rats, one hypertensive (SHR) and the other normotensive (WKY), were investigated. Prior to determining the technical conditions for transfer, the reproductive characteristics of each strain were studied in order to determine whether they were significantly different. Differences between the two strains were found in ovulation rate, percentage of abnormal pre-implantation embryos and gestation length; litter size and maternal weight gain during pregnancy were not significantly different. For transfers, three protocols for synchrony of embryo and uterine development were tested, and optimal conditions were found to exist with the transfer of day-5 WKY embryos to day-5 SHR pseudopregnant recipients (74% successful pregnancies), and the transfer of day-4 SHH embryos to day-4 pseudopregnant WKY recipients (53% successful pregnancies). The data indicate that some of the reproductive ch...