Effect of relaxin on motility, acrosome reaction and viability of cryopreserved boar spermatozoa

Abstract

Relaxin has an important role in stimulating motility and the acrosome reaction (AR) of fresh boar spermatozoa. The objective of the present study was to determine whether relaxin can improve the motility, AR and viability of cryopreserved boar spermatozoa. Cryopreserved boar spermatozoa were thawed, washed and incubated at 37°C for 4 h in modified Beltsville thawing solution supplemented with 0, 20 or 40 ng/mL relaxin. Sperm motility, AR, viability, and incorporation and oxidation ofC-glucose were evaluated during 0-4 h of incubation. The results show that the supplementation of relaxin (especially at 20 ng/mL) in the thawing solution improved sperm motility significantly ( < 0.05) at 1-3 h of incubation. The percentage of acrosome reacted live spermatozoa was improved significantly ( < 0.05) when the spermatozoa were treated with 20 ng/mL relaxin. Viability was not significantly ( > 0.05) improved by supplementation with relaxin. The rates of incorporation and oxidation of C-glucose were increased in correlation with AR up to 4 h of incubation. We conclude that relaxin can improve the sperm motility and AR, and enhance the glucose metabolism of cryopreserved boar spermatozoa. (Reprod Med Biol 2006; : 215-220).

Physiological roles of relaxin in prefertilizing activities of spermatozoa

“…Relaxin has important roles in improving sperm motility in human (Lessing et al, 1985), porcine (Juang et al, 1989;Kohsaka et al, 2001;Miah et al, 2006aMiah et al, ,b, 2008Han et al, 2006) and bovine spermatozoa (Miah et al, 2007). However, the role of relaxin in other sperm physiological events or phenomena like capacitation, acrosome reaction, and their mediating factors associated with successful fertilization were unknown prior to our recent investigations (Miah et al, 2011).…”

“…3. Relaxin has little effect on viability of fresh or frozen-thawed porcine or bovine spermatozoa (Miah et al, 2006a(Miah et al, ,b, 2007(Miah et al, , 2008. The viability of spermatozoa in the female reproductive tract is 4-6 h (Pursel et al, 1978).…”

“…6; Miah et al, 2006aMiah et al, ,b, 2007Miah et al, , 2008. Mukai and Okuno (2004) suggested that glycolysis played a major role in providing ATP for sperm flagellar movement.…”

“…Different letters or * indicate significant differences (P < 0.05) among the treatments in the same incubation period. The figures (a-d) were reproduced from our previous studies (Miah et al, 2006a(Miah et al, ,b, 2007 and (e) from the study of Ferlin et al (2012).…”

“…If relaxin is added to post-thaw washed spermatozoa, it improves the rate of progressive motility of frozen-thawed porcine spermatozoa (Miah et al, 2006a). Lessing et al (1986) reported that relaxin in physiologic concentrations (10-100 ng/ml) had no significant effect on sperm motility in normal semen samples.…”