33 PROPAGATION OF ELITE LIFESAVER DOGS BY SOMATIC CELL NUCLEAR TRANSFER

Abstract

Canine somatic cell nuclear transfer (cSCNT) has been used as a useful tool for propagation of elite working dogs. In 2009, 7 cloned dogs were successfully produced using somatic cells derived from the excellent drug-sniffing dog of Korea Customs Service. All cloned dogs perfectly performed drug detection in Incheon International Airport. The objective of the present study was to compare the efficiency of the 2 activation culture media to clone the retired Baekdu, a veteran rescue dog that performed lifesaving activities worldwide for 6 years in Korea National Emergency Management Agency (NEMA). Ear tissue was collected from a 10-year-old male German Shepherd and fibroblasts were cultured for cSCNT. The cells were injected into the perivitelline space of enucleated in vivo-matured dog oocytes, fused with electric stimulation using an electro cell fusion apparatus (Nepa Gene Co. Ltd.), and activated chemically. In the activation protocol, 2 different types of media were tested to investigate the effect of proteins with undefined functions. The first medium was a modified synthetic oviduct fluid (mSOF), which is a complex culture medium with BSA that includes undefined functions. The second medium was the porcine zygote medium (PZM-5), which is a chemically defined medium with polyvinyl alcohol (PVA). The fused couplets were activated by mSOF medium supplemented with 1.9 nM DMAP (SOF-DMAP), and PZM-5 supplemented with 1.9 nM DMAP (PZM-DMAP) for 4 h, followed by 4 min of calcium ionophore treatment. Then, reconstructed oocytes were transferred into the uterine tube of naturally estrus-synchronized surrogate dogs. In the PZM-DMAP group, a total of 56 activated cloned embryos were transferred into 3 female recipient dogs, and a total of 64 activated cloned embryos from the SOF-DMAP group were transferred into 4 female recipients. Pregnancy diagnosis was performed using a SONOACE 9900 (Medison, Seoul, Korea) ultrasound scanner with 7.0-MHz linear-array probe between 30 and 35 days after embryo transfer. As a result, pregnancy was detected in 1 out of 3 surrogate mothers that received cloned embryos from the PZM-DMAP group (33.3%), and 1 pregnancy (25%) was detected in 4 surrogate mothers receiving cloned embryos from the SOF-DMAP group. Two pregnant dogs each gave birth to 1 healthy cloned puppy by cesarean section. This study shows that existence of proteins with undefined functions in activation medium did not affect the dog cloning. In addition, the number of elite working dogs in diverse fields can be increased by the NT technique using donor cells derived from small tissue of elite working dogs.

This study was supported by RDA (no. PJ0089752012), RNL Bio (no. 550-20120006), IPET (no. 311062-04-1-SB010), Research Institute for Veterinary Science, and TS Corporation.