Takenaka Motoo, Yagi Mio, Amakasu Kohei, Suzuki Katsushi, Suzuki Hiroetsu
Laboratory of Veterinary Physiology, Nippon Veterinary Life Science University, 1-7-1 Kyonancho, Musashino-shi, Tokyo 180-8602, Japan.
J Androl. 2008 Nov-Dec;29(6):669-78. doi: 10.2164/jandrol.108.005066. Epub 2008 Jul 31.
The lde/lde rats show a severe dwarf phenotype with early postnatal lethality and a high incidence of epileptic seizure. Seizures are first detected in this model between 16 and 63 days of age, and mostly begin as wild running and progress to generalized tonic-clonic convulsions. Because our histological examination detected many extracellular vacuoles in the hippocampus and amygdaloid bodies of these animals at 28 days of age, these pathological alterations may be related to the epileptogenesis in lde/lde rats. In addition to these defects, male lde/lde rats have apparently smaller testes with reduced number of germ cells and poorly matured adult-type Leydig cells in comparison with wild-type controls. In the present study, we performed anatomical, histological, and endocrinologic examinations to characterize the testicular phenotype of lde/lde rats at 21, 28, 35, and 56 days of age. Male lde/lde rats showed severely retarded growth of the testes and accessory sex organs. Their seminiferous tubules were significantly smaller and contained markedly fewer germ cells at all time points examined as compared with controls. Significantly fewer Sertoli cells at 21 and 28 days of age, markedly decreased spermatocyte number at 28 days of age, and delayed appearance of spermatids at 56 days of age were observed in the testes of lde/lde rats. More TUNEL (T&T-mediated duTP-biotin nick-end labeling)-positive cells were detected in lde/lde seminiferous tubules, and the largest number of apoptotic cells was recorded at 28 days of age. The increases in 3beta-hydroxysteroid dehydrogenase-positive adult-type Leydig cells and 11beta-hydroxysteroid dehydrogenase-positive mature adult-type Leydig cells were also severely retarded in the testes of lde/lde rats. Consistent with these defects, significantly lower plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone concentrations were detected in lde/lde males at 28 days of age, and weak immunostaining for FSH and smaller cytoplasm of LH-positive cells were detected in the anterior pituitary lobes of lde/lde males. Despite a normal level of plasma LH after 35 days of age, a significantly lower level of plasma testosterone was detected at 56 days of age. These results indicate that the normal lde allele is related to prepubertal elevations of gonadotropins and normal development of adult-type Leydig cells. Because lde/lde rats experience epileptic seizures during the period when the hypothalamus-pituitary-testicular axis is established, lde/lde rats would be useful as a model for reproductive disorder with pediatric epilepsy.
Lde/lde大鼠表现出严重的侏儒表型，出生后早期致死率高，癫痫发作发生率高。在该模型中，癫痫发作最早在16至63日龄时被检测到，大多始于狂奔，随后发展为全身性强直阵挛性惊厥。因为我们的组织学检查在这些动物28日龄时检测到海马体和杏仁核中有许多细胞外空泡，所以这些病理改变可能与Lde/lde大鼠的癫痫发生有关。除了这些缺陷外，与野生型对照相比，雄性Lde/lde大鼠的睾丸明显较小，生殖细胞数量减少，成年型睾丸间质细胞成熟不良。在本研究中，我们进行了解剖学、组织学和内分泌学检查，以表征21、28、35和56日龄Lde/lde大鼠的睾丸表型。雄性Lde/lde大鼠的睾丸和附属生殖器官生长严重迟缓。在所有检查时间点，其生精小管明显较小，生殖细胞数量明显少于对照组。在Lde/lde大鼠的睾丸中，观察到21和28日龄时支持细胞数量明显减少，28日龄时精母细胞数量明显减少，56日龄时精子细胞出现延迟。在Lde/lde生精小管中检测到更多TUNEL（末端脱氧核苷酸转移酶介导的dUTP生物素缺口末端标记）阳性细胞，28日龄时凋亡细胞数量最多。Lde/lde大鼠睾丸中3β-羟基类固醇脱氢酶阳性的成年型睾丸间质细胞和11β-羟基类固醇脱氢酶阳性的成熟成年型睾丸间质细胞的增加也严重迟缓。与这些缺陷一致，在28日龄的Lde/lde雄性大鼠中检测到血浆促卵泡激素（FSH）、促黄体生成素（LH）和睾酮浓度显著降低，在Lde/lde雄性大鼠的垂体前叶中检测到FSH免疫染色较弱和LH阳性细胞的细胞质较小。尽管35日龄后血浆LH水平正常，但在56日龄时检测到血浆睾酮水平显著降低。这些结果表明，正常的Lde等位基因与青春期前促性腺激素升高和成年型睾丸间质细胞的正常发育有关。由于Lde/lde大鼠在下丘脑-垂体-睾丸轴建立期间会发生癫痫发作，Lde/lde大鼠将作为小儿癫痫伴生殖障碍的模型。
