Toward using stable spermatozoal RNAs for prognostic assessment of male factor fertility

Objective

To establish the stability of spermatozoal RNAs as a means to validate their use as a male fertility marker.

Design

Semen samples were randomly selected for 1 of 3 cryopreservation treatments.

Setting

An academic research environment.

Patient(s)

Men aged 19 to 55 years who had fathered a child by natural conception within the past 6 months.

Intervention(s)

Ejaculates were collected by masturbation and total spermatozoan RNA was isolated from two semen samples of ideal quality; one sample of medium quality, having been subjected to an additional freeze-thaw cycle, and two samples of poor quality, having been subjected to a third freeze-thaw cycle.

Main Outcome Measure(s)

Labeled cDNAs were generated and then used to interrogate Atlas Nylon Human Toxicology 1.2 microarrays. The spermatozoan transcriptomes were compared using a binomial approach.

Result(s)

The analysis identified a total of 228 unique spermatozoal transcripts among all samples. The medium quality sample shared 98% and 39% of its RNAs with the ideal and poor quality samples, respectively. A set of 36 RNAs resistant to insult were observed, some of which have been implicated in regulating male fertility, when all individuals were compared.

Conclusion(s)

These results support the view that a population of spermatozoal RNAs is rapidly degraded in response to insult, whereas another population appears protected from such damage. Because spermatozoal RNAs echo the gene expression of spermatogenesis, the latter is likely to prove useful as a clinical maker of fertility status.

Key Words:  Cryopreservation , microarray , sperm transcripts , RNA , diagnosis