Effects of bovine serum albumin on function of cryopreserved stallion spermatozoa during medium culture and uterine tube epithelial cell coculture

OBJECTIVE: To compare function of cultured cryopreserved stallion spermatozoa in a modified Tyrode's medium (TM), with or without bovine serum albumin (BSA), or in uterine tube (oviduct) epithelial cell (OEC) coculture in TM, with or without BSA. SAMPLE POPULATION: Cryopreserved spermatozoa from 6 proven stallions and OEC from bovine reproductive tracts in follicular phase. PROCEDURE: Thawed spermatozoa were cultured in TM, with or without BSA, or cocultured with OEC monolayers in TM, with or without BSA. Percentages of capacitated and acrosome-reacted spermatozoa were measured at 5 hours for TM cultures. Spermatozoal survival and motility characteristics were observed over time for all culture methods. Number of spermatozoa attaching to OEC were compared for cocultures. RESULTS: Use of TM without BSA altered spermatozoal function in cell-free medium culture and OEC coculture. A higher percentage of spermatozoa were acrosome reacted in TM with BSA, although percentages of capacitated spermatozoa did not differ. Spermatozoa survived longer and maintained superior motion in TM culture without BSA and in OEC cocultures. More spermatozoa were able to attach to OEC in TM without BSA. CONCLUSIONS: Incubation of cryopreserved spermatozoa in media with BSA resulted in rapid decrease in percentage of intact, motile spermatozoa and limited their ability to interact with OEC. CLINICAL RELEVANCE: Current culture media used for assisted reproduction techniques in horses do not provide functionally capacitated spermatozoa. Removal of BSA from such media improves spermatozoal quality and survival.