Rhesus offspring produced by intracytoplasmic injection of testicular sperm and elongated spermatids.

OBJECTIVE

To establish pregnancies in rhesus monkeys using testicular sperm and elongated spermatids injected into oocytes.

DESIGN

Comparative animal study.

SETTING

Regional Primate Research Center.

ANIMAL(S): Prime, fertile rhesus monkeys.

INTERVENTION(S): Oocytes collected by laparoscopy from gonadotropin-stimulated female rhesus monkeys were injected with testicular sperm or elongated spermatids obtained from the testis of males. Cleavage stage embryos were transferred to surrogate females.

MAIN OUTCOME MEASURE(S): Fertilization, embryo cleavage, and the establishment of pregnancies. Fertilization failures were fixed and processed for the detection of microtubules and chromatin configurations.

RESULT(S): Fertilization, assessed by the presence of two pronuclei within 15 hours after injection, was 60% for intracytoplasmic sperm injection with testicular sperm and 47% for elongated spermatid injection. Fertilized zygotes co-cultured in Connaughts Medical Research Labs (CMRL) medium on a Buffalo Rat Liver cell monolayer resulted in hatched blastocysts after testicular sperm extraction-intracytoplasmic sperm injection and elongated spermatids. Embryos transferred at the 4- to 8-cell stage gave rise to three pregnancies: 2/3 from testicular sperm and 1/1 from an elongated spermatid. Three healthy infants were delivered by cesarean. Oocytes that failed to fertilize typically remained arrested in metaphase of meiosis.

CONCLUSION(S): Testicular sperm and elongated spermatids can be used for fertilization in the rhesus monkey resulting in live births.