Production of transgenic rats by ooplasmic injection of spermatogenic cells exposed to exogenous DNA: A preliminary study

The aim of the present study was to investigate the efficiencies of producing transgenic rats by the ooplasmic injection of sperm heads (intracytoplasmic sperm injection: ICSI) and elongating spermaticls (elongating spermatid injection: ELSI) exposed to the EGFP DNA solution. A slightly lower proportion of ICSI oocytes using sperm heads exposed to a concentration of 0.5 mug/ml DNA solution for 1 min developed into offspring (13.3%, 48/361) when compared to that of oocytes injected with nontreated sperm heads (19.4%, 32/165). Eight ICSI offspring were found to be EGFP-carrying transgenic rats (16.7% per offspring; 2.2% per embryo). After a 1-min exposure of the elongating spermatids to 5 mug/ml of DNA solution, 8.8% (45/511) of the ELSI oocytes developed into offspring while 12.7% (22/173) of the ELSI oocytes using nontreated spermaticls developed. Six ELSI offspring carried the EGFP DNA (13.3% per offspring; 1.2% per embryo). The conventional pronuclear micro-injection of 5 mug/ml of DNA solution resulted in the higher production of offspring (29.7%, 104/350) and the birth of three transgenic rats (2.9% per offspring; 0.9% per embryo). Thus, sperm heads and elongating spermatids were practically useful as the vector of exogenous DNA if the DNA-exposed spermatogenic cells were microinseminated into rat oocytes. (C) 2004 Wiley-Liss, Inc.