Assessment of released acrosin activity as a measurement of the sperm acrosome reaction

Aim： To develop a method for assessing sperm function by measuring released acrosin activity during the acrosome reaction （AR）. Methods： Human semen samples were obtained from 24 healthy donors with proven fertility after 3-7 days of sexual abstinence. After collection, samples were liquefied for 30 min at room temperature. Standard semen parameters were evaluated according to World Health Organization （WHO） criteria. Calcium ionophore A23187 and progesterone （P4） were used to stimulate the sperm to undergo AR. After treatment, sperm were incubated with the supravital dye Hoechst33258, fixed in a glutaraldehyde-phosphate-buffered saline solution, and the acrosomal status was determined by fluorescence microscopy with fluorescein isothiocyanate-labeled Pisum sativum agglutinin （FITC-PSA）. The percentage of sperm undergoing AR （AR%） was compared to sperm acrosin activities as assessed by spectrocolorimetry. The correlation between AR% and acrosin activity was determined by statistical analysis. Results： The AR% and released acrosin activity were both markedly increased with A23187 and P4 stimulation. Sperm motility and viability were significantly higher after stimulation with P4 versus stimulation with A23187 （P 〈 0.001）. There was a significant positive correlation between released acrosin activity and AR% determined by FITC-PSA staining （r= 0.916, P 〈 0.001）. Conclusion： Spectrocolorimetric measurement of released acrosin activity might serve as a reasonable alternative method to evaluate AR. （Asian J Androl 2008 Mar, 10： 236-242）

Roles of tumor necrosis factor alpha on sperm acrosin activity and acrosome reaction

Aim: To study the roles of tumor necrosis factor alpha (TNF-α) on the sperm acrosin activity and acrosome reaction. Methods: The sperm acrosin activity was tested by the method of BAEE/ ADH Unity and the acrosome reaction by the Triple-stain technique. Results: TNF-α decreased the sperm acrosin activity and acrosome reaction (P<0.01; P<0.01, respectively); it also inhibited the Ca2+-ATPase activity and SOD activity in sperm (P< 0.05; P<0.001, respectively), but increased the NOS activity and the amount of NO in sperm (P<0.001; P<0.001, respectively). While it had a less significant effect on the activity of Na+-K+-ATPase (P>0.05). Conclusion: TNF-α inhibits the sperm acrosin activity and acrosome reaction.

Sperm acrosin activity may be a useful factor in choosing between ICSI and IVF for infertile male patients

The clinical applications of acrosin activity are limited.We analyzed 61578 male partners in infertile couples who visited the outpatient department of the Reproductive and Genetic Hospital of CITIC-Xiangya(Changsha,China)between August 2014 and December 2019 to determine the reference ranges and thresholds for acrosin activity in infertile Chinese men;to determine whether correlations exist between acrosin activity and age,sperm concentration,sperm morphology,or sperm motility;and to evaluate whether acrosin activity could serve as an effective prognostic indicator for choosing between in vitro fertilization(IvF)and intracytoplasmic sperm injection(icsl)in the clinic.The cut-off value for the normal reference range of acrosin activity for male partners in infertile couples was 24.78μlU per 106 sperm.There was no significant association between acrosin activity and age,sperm concentration,semen volume,total sperm count,progressive motility,or total motile spermatozoa.A weak positive correlation was found between acrosin activity and normal sperm morphology.There was a statistically significant difference in abnormal acrosome morphology between the group with high acrosin activity(>24.78μlU per 106 sperm)and the group with low acrosin activity(<24.78μlU per 106 sperm).The group with a low IVF fertilization rate had a high index of abnormal acrosomal morphology at 21.2%,while the group with a high IVF fertilization rate had a low index of 0.2%.At an acrosin activity of<24.78μlU per 10 sperm,in one cycle of the same patient,the fertilization rate,normal fertilization rate,and good-quality embryo rate for Icsl were significantly higher than those for IVF.Therefore,the most promising application of acrosin activity could be in the selection of IcsI over IVF for infertile male patients with complete fertilization failure or a low fertilization rate.