男性不妊における精子授精能に関する研究 - 透明帯除去ハムスター卵精子侵入試験とヒト精子授精能 -

Abstract

正常男性50名と不妊男性58名に透明帯除去ハムスター卵を使用した精子侵入試験(SPA)を施行したところ精子侵入率(中央値)はそれぞれ68%(13%～100%), 11%(0%～100%)で不妊男性では低値であった.正常男性および不妊男性ともに精子侵入率と従来の精子パラメータとの間に相関は認められなかった.SPAの不妊診断率は72.4%と他のパラメータに比べて高率であり, 男性妊孕能に最も関連する可能性が示唆された.これに対し従来重視されてきた精子濃度の不妊診断率は36.8%と低かった.従来の精液検査では正常と評価される「いわゆる原因不明不妊夫婦の夫」にSPAを施行し, 精子侵入率10%未満の症例が36例中8例(22%)に認められ, 精子授精能の低下が不妊原因となっている可能性が示唆された

Zona free hamster egg-sperm penetration assay (SPA) was performed on 50 normal fertile men and 58 infertile men. The median penetrating rate was 68% (13%-100%) for the fertile men and 11% (0-100%) for the infertile men. These existed no clear relationship between SPA and any other sperm parameters. SPA showed the best diagnostic rate (72.4%) for male infertility, which was evaluated by the 95% specificity threshold values of normal males. Therefore, SPA is best correlated with male impregnating ability. On the contrary, the infertile diagnostic rate of sperm density was relatively low (36.8%). SPA was also carried out on male partners of unexplained infertility couples, and 8 out of 36 (22%) showed decreased sperm penetration rate (less than 10%). In these couples, the deterioration of fertilizing ability was thought to be one of the causative factors of infertility.