Richard W. Lenz

Structural comparisons among glycosaminoglycans to promote an acrosome reaction in bovine spermatozoa.

Bovine epididymal spermatozoa were cultured for 22 hr. in a chemically defined medium containing glycosaminoglycans. Sperm were stained and examined for degree of acrosome reactions and viability after treatment. Viability did not differ significantly among treatments or doses. Highly significant treatment and dose effects resulted for induction of the acrosome reaction. Heparin was the most potent glycosaminoglycan and hyaluronic acid was least effective. Chondroitin sulfate isomers yielded a response intermediate to heparin or hyaluronic acid. These results suggested that the degree of sulfation of the glycosaminoglycans was partly responsible for promoting the acrosome reaction. Treatment of chondroitin sulfate isomers with chondro-4-sulfatase or chondro-6-sulfatase showed that the respective stimulatory effects of chondroitin-4-sulfate and chondroitin-6-sulfate were negated. It was concluded that the ability of glycosaminoglycans to induce the acrosome reaction in bovine spermatozoa in vitro resides in the amino-sugar complex and is enhanced by the presence of a sulfate moiety on the amino-sugar disaccharide.

Proteoglycan from bovine follicular fluid enhances an acrosome reaction in bovine spermatozoa

Abstract Bovine epididymal and ejaculated spermatozoa were incubated for 22 and 9.5 h respectively, in a chemically defined medium. The percentages of sperm exhibiting an acrosome reaction were determined morphologically after fixing and staining specimens. Addition of bovine follicular proteoglycan or chondroitin sulfates ABC significantly increased the incidence of acrosome reaction. The stimulatory effects of the proteoglycan or chondroitin sulfates were negated by exposure to the enzyme chondroitinase ABC. Viability of spermatozoa was not affected by the various experimental treatments. Transmission electron microscopy of spermatozoa showed that vesiculation had occurred between the plasma and outer acrosomal membrane. These results suggest that proteoglycan present in follicular fluid at the time of ovulation may promote the acrosome reaction which precedes the ability of sperm to fertilize an ovum.