精子缺陷和受精失败

Spermatozoa defect and fertilization failure

不育症是当今一个重要的健康问题，有大约15％的夫妇都在为生育寻求临床治疗。在所有不能自然受孕的夫妇中，多达三分之二的夫妇是由男性生育力的下降导致的。尽管我们在生物学和生理学上对于受精的认识已有很大进步，但仍然不能解释受精失败的潜在原因。即使是在不育的男性中发现有精索静脉曲张、生殖器感染或抗精子抗体，这些因素对于不育症病因的解释价值尚不明确。

The fertilization failure in vitro is related to many factors, such as sperm defect, oocyte defect, culture system, contaminations/infections and technical problem, etc. Although spermatozoa are usually selected by swim-up migration or gradient selection, and only a low number of motile spermatozoa are needed for successful in-vitro fertilization or ICSI, failure of fertilization or cleavage is observed in 15%-30 % of cases showing normal semen characteristics. Such fertilization failure may be due to technical factors as well as to the quality of the gametes. In addition, it has been shown that the fertilization rate or the proportion of embryos undergoing cleavage decreases when the seminal sperm concentration, and/or the percentages of motility or normal morphology are reduced. However, the spermatogenic defect is genetic anomalies, which might be a potential risk of transmitting this defect to future offspring. Therefore, genetic counseling of all couples with the diagnosis of male infertility is recommended before their enrolment in intrauterine insemination, in vitro fertilization, and intracytoplasmic sperm injection. The important role of genetic abnormalities in the causation of human male infertility is increasingly recognized. While much remains to be learned in this fast-moving field, considerable progress has been made in the clinical delineation of genetic forms of male infertility and in the characterization of the responsible genes and their mutations or deletions. This review should provide insight into the understanding of fertilization failure in the human IVF, which is related to spermatogenic defect.