Deterioration of stored culture media as monitored by a sperm motility bioassay.

A hamster sperm motility bioassay was used to monitor medium quality during storage. The media studied were (1) TL-PVA, a modified Tyrode's solution; (2) TLP-PVA, a defined medium that supports hamster sperm motility but does not support capacitation; and (3) TALP-PVA (TLP-PVA + serum albumin), which supports hamster sperm survival and capacitation. Each medium was stored at 5 and -20 degrees C and tested every two weeks. All of the media deteriorated with increased storage time, but at different rates (TLP-PVA greater than TL-PVA greater than TALP-PVA). The deterioration of the media correlated with an increase in pH during storage, probably due to a loss of CO2 and bicarbonate. Albumin, added after storage, was able to rescue frozen TL-PVA.