Boitrelle Florence, Albert Martine, Theillac Claire, Ferfouri Fatma, Bergere Marianne, Vialard François, Wainer Robert, Bailly Marc, Selva Jacqueline
Department of Reproductive Biology, University Department 2493, Poissy Hospital, Poissy, France.
J Androl. 2012 Nov-Dec;33(6):1371-8. doi: 10.2164/jandrol.112.016980. Epub 2012 Jun 14.
Even though cryopreservation of human spermatozoa is known to alter sperm motility and viability, it may also induce nuclear damages. The present study set out to determine whether or not cryopreservation alters motile sperm morphology under high magnification and/or is associated with chromatin decondensation. For 25 infertile men, we used high-magnification microscopy to determine the proportions of various types of motile spermatozoa before and after freezing-thawing: morphometrically normal spermatozoa with no vacuole (grade I), ≤ 2 small vacuoles (grade II), at least 1 large vacuole or >2 small vacuoles (grade III), and morphometrically abnormal spermatozoa (grade IV). The spermatozoa's chromatin condensation and viability were also assessed before and after freezing-thawing. Cryopreservation induced sperm nuclear vacuolization. It decreased the proportion of grade I + II spermatozoa (P < .001). It induced a decrease in the sperm viability rate (P < .001) and increased the proportion of sperm with noncondensed chromatin (P < .001). The latter parameter was strongly correlated with sperm viability (r = 0.71; P < .001). However, even motile sperm presented a failure of chromatin condensation after freezing-thawing, because the proportion of sperm with noncondensed chromatin was correlated with high-magnification morphology (r = -0.49 and 0.49 for the proportions of grade I + II and grades III + IV, respectively; P < .001). Cryopreservation alters the organelle morphology of motile human spermatozoa and induces sperm chromatin decondensation. High-magnification microscopy may be useful for evaluating frozen-thawed spermatozoa before use in assisted reproductive technology procedures (such as intrauterine insemination, in vitro fertilization, and intracytoplasmic sperm injection) and for performing research on cryopreservation methods. If frozen-thawed sperm is to be used for intracytoplasmic sperm injection, morphological selection under high magnification may be of particular value.
尽管已知人类精子的冷冻保存会改变精子活力和生存能力，但它也可能导致细胞核损伤。本研究旨在确定冷冻保存是否会在高倍放大下改变活动精子的形态，和/或是否与染色质解聚有关。对于25名不育男性，我们使用高倍显微镜来确定冻融前后各种类型活动精子的比例：无液泡的形态正常精子（I级）、≤2个小液泡（II级）、至少1个大液泡或>2个小液泡（III级）以及形态异常精子（IV级）。还在冻融前后评估了精子的染色质凝聚和生存能力。冷冻保存导致精子细胞核空泡化。它降低了I + II级精子的比例（P <.001）。它导致精子存活率下降（P <.001），并增加了染色质未凝聚精子的比例（P <.001）。后一个参数与精子活力密切相关（r = 0.71；P <.001）。然而，即使是活动精子在冻融后也出现了染色质凝聚失败的情况，因为染色质未凝聚精子的比例与高倍放大形态相关（I + II级和III + IV级比例的r分别为-0.49和0.49；P <.001）。冷冻保存会改变活动人类精子的细胞器形态并诱导精子染色质解聚。高倍显微镜可用于在辅助生殖技术程序（如宫内人工授精、体外受精和卵胞浆内单精子注射）中使用冻融精子之前进行评估，以及用于冷冻保存方法的研究。如果将冻融精子用于卵胞浆内单精子注射，高倍放大下的形态选择可能具有特别的价值。
