Foster Warren G, Maharaj-Briceño Serena, Cyr Daniel G
Department of Obstetrics and Gynecology, McMaster University, ON, Canada.
Cien Saude Colet. 2011 Jun;16(6):2893-905. doi: 10.1590/s1413-81232011000600027.
A single in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gestation day 15 decreased epididymal sperm count in adult rats and thus was used to establish a tolerable daily intake for TCDD. However, several laboratories have been unable to replicate these findings. Moreover, conflicting reports of TCDD effects on daily sperm production suggest that spermatogenesis may not be as sensitive to the adverse effects of TCDD as previously thought. We performed a PubMed search using relevant search terms linking dioxin exposure with adverse effects on reproduction and spermatogenesis. Developmental exposure to TCDD is consistently linked with decreased cauda epididymal sperm counts in animal studies, although at higher dose levels than those used in some earlier studies. However, the evidence linking in utero TCDD exposure and spermatogenesis is not convincing. Animal studies provide clear evidence of an adverse effect of in utero TCDD exposure on epididymal sperm count but do not support the conclusion that spermatogenesis is adversely affected. The mechanisms underlying decreased epididymal sperm count are unknown; however, we contest [corrected] that epididymal function is the key target for the adverse effects of TCDD.
在妊娠第15天对大鼠进行单次子宫内2,3,7,8 - 四氯二苯并 - p - 二恶英（TCDD）暴露，会降低成年大鼠附睾精子数量，因此该暴露被用于确定TCDD的每日耐受摄入量。然而，多个实验室未能重复这些结果。此外，关于TCDD对每日精子生成影响的报告相互矛盾，这表明精子发生可能不像之前认为的那样对TCDD的不良反应敏感。我们使用相关检索词在PubMed上进行了检索，这些检索词将二恶英暴露与对生殖和精子发生的不良反应联系起来。在动物研究中，发育阶段暴露于TCDD始终与附睾尾部精子数量减少有关，尽管所使用的剂量水平高于一些早期研究。然而，将子宫内TCDD暴露与精子发生联系起来的证据并不令人信服。动物研究提供了子宫内TCDD暴露对附睾精子数量产生不利影响的明确证据，但并不支持精子发生受到不利影响这一结论。附睾精子数量减少的潜在机制尚不清楚；然而，我们认为附睾功能是TCDD不良反应的关键靶点。
