Novel insights into necrozoospermia from a single-center study:reference ranges,possible etiology,and impact on male fertility

Necrozoospermia is a poorly documented condition with a low incidence,and its definition and clinical significance are unclear.Herein,we provide a reference range for necrozoospermia and discuss its possible etiology and impact on male fertility and assisted reproductive outcomes.We extracted relevant information from 650 Chinese male partners of infertile couples and statistically analyzed sperm vitality.Necrozoospermia was present in 3.4%(22/650)of our study population,and the lower cut-off value for sperm vitality was 75.3%.We compared two methods for assessing sperm vitality(eosin-nigrosin head staining and hypo-osmotic swelling test[HOST]),for which the percentage in the eosin-nigrosin group(mean±standard deviation[s.d.]:77.5%±10.5%)was significantly higher than that in the HOST group(mean±s.d.:58.1%±6.7%[5-10 min after incubation]and 55.6%±8.2%[25-30 min after incubation];both P<0.001).The incidence of necrozoospermia increased with age(odds ratio[OR]=1.116,95%confidence interval[CI]:1.048-1.189,P=0.001),while the percentage of normal sperm morphology and DNA fragmentation index(DFI)were significantly associated with necrozoospermia,with ORs of 0.691(95%CI:0.511-0.935,P=0.017)and 1.281(95%CI:1.180-1.390,P<0.001),respectively.In the following 6 months,we recruited 166 patients in the nonnecrozoospermia group and 87 patients in the necrozoospermia group to compare intracytoplasmic sperm injection(ICSI)and pregnancy outcomes between the two groups.The necrozoospermia group had a significantly lower normal fertilization rate(74.7%vs 78.2%,P=0.041;OR=0.822;95%CI:0.682-0.992)than that in the nonnecrozoospermia group.This study presents substantial information on necrozoospermia to establish comprehensive and applicable reference values for sperm vitality for spontaneous conception and artificially assisted reproductive management.

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.