A team of scientists from the Universities of Pennsylvania and California, in the US, has created viable monkey sperm in mice, using transplanted testicular tissue. From the date of the transplant, it took seven months for mature live sperm to be produced in the grafted tissue.

The researchers, who have published their work in the journal Biology of Reproduction, say that the initial purpose of the technique is to reduce the amount of experimentation on primates, but also that it could be used to help conserve endangered species. The scientists also say that it may be possible for human sperm to be grown in the same way - meaning that the technique could eventually be used to treat male infertility, particularly for men made infertile by cancer treatment undertaken before they reach puberty.

The researchers took tissue from the testis of a 13-month old rhesus macaque monkey and implanted it under the skin on the back of a mouse with a 'knocked-out' immune system. This minimised the likelihood that the foreign tissue would be rejected. The mice used were also castrated, so they would produce a higher level of the hormone that switches on sperm production. This meant that the transplanted skin grew faster.

In the immediate future, the scientists say that they will embark on a trial with domestic cats, building up to work with big cats, which rarely survive to reproductive age in captivity.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.