Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia.
J Urol. 2012 Oct;188(4 Suppl):1443-8. doi: 10.1016/j.juro.2012.02.041. Epub 2012 Aug 17.
Inguinoscrotal testicular descent has been proposed to occur via sensory fibers of the sexually dimorphic genitofemoral nerve, which release a neurotransmitter, calcitonin gene related peptide, to guide the migrating gubernaculum into the scrotum. We hypothesize that androgen mediated regression of the genitofemoral nerve mammary branch is necessary for inguinoscrotal descent in rats. We compared the spatiotemporal development of the genitofemoral nerve in control and antiandrogen treated rats.
A total of 29 Sprague-Dawley® rats were collected (animal ethics committee approval A644) in control and antiandrogen treated groups (flutamide, embryonic days 16 to 19, 75 mg/kg body weight/5% ethanol + oil) on embryonic days 17 and 19, and on postnatal day 2. Sagittal sections of the gubernaculum and its surrounding structures were processed for standard histology and immunohistochemistry for androgen receptor, nerves (Tuj1), calcitonin gene related peptide (marker for genitofemoral nerve) and cell nuclei (DAPI).
The inguinal mammary bud, its adjacent androgen receptor and genitofemoral nerve mammary branch (containing calcitonin gene related peptide) persisted from embryonic day 17 to postnatal day 2 in all antiandrogen treated males, yet regressed in all control males by postnatal day 2.
Antiandrogens resulted in the persistence of the mammary branch and inguinal mammary bud. Persistent genitofemoral nerve mammary branches may arrest or slow down gubernacular migration by releasing calcitonin gene related peptide in the mammary inguinal fat pad, thus reducing the chemotactic gradient to calcitonin gene related peptide from genitofemoral nerve branches in the distal scrotum. We hypothesize that this process may be related to antiandrogen induced cryptorchidism in the rodent.
有人提出，腹股沟阴囊睾丸下降是通过性二态性生殖股神经的感觉纤维发生的，该纤维释放神经递质降钙素基因相关肽，以引导迁移的精索进入阴囊。我们假设雄激素介导的生殖股神经乳腺支的退化对于大鼠的腹股沟阴囊下降是必要的。我们比较了对照组和抗雄激素处理大鼠生殖股神经的时空发育。
共收集 29 只 Sprague-Dawley®大鼠（动物伦理委员会批准 A644），在对照组和抗雄激素处理组（氟他胺，胚胎第 16 至 19 天，75mg/kg 体重/5%乙醇+油）中，在胚胎第 17 天和第 19 天以及出生后第 2 天收集。对精索及其周围结构的矢状切片进行标准组织学处理，并进行雄激素受体、神经（Tuj1）、降钙素基因相关肽（生殖股神经标志物）和细胞核（DAPI）的免疫组织化学染色。
腹股沟乳腺芽及其相邻的雄激素受体和生殖股神经乳腺支（包含降钙素基因相关肽）在所有抗雄激素处理的雄性大鼠中从胚胎第 17 天持续到出生后第 2 天，但在所有对照组雄性大鼠中均在出生后第 2 天消退。
抗雄激素导致乳腺支和腹股沟乳腺芽的持续存在。生殖股神经乳腺支的持续存在可能通过在乳腺腹股沟脂肪垫中释放降钙素基因相关肽来阻止或减缓精索迁移，从而减少从远端阴囊的生殖股神经分支到降钙素基因相关肽的趋化梯度。我们假设，这个过程可能与抗雄激素诱导的啮齿动物隐睾有关。
