Hussein Mahmoud R, Abu-Dief Eman E, Abou El-Ghait Amal T, Adly Mohamed A, Abdelraheem Mohamad H
Department of Histopathology, Assuit University Hospitals, Faculty of Medicine, Assuit, Egypt.
Int J Exp Pathol. 2006 Jun;87(3):237-50. doi: 10.1111/j.1365-2613.2006.00480.x.
Irradiation has profound effects on the reproductive function. Our knowledge about radioprotective effects of melatonin against X-ray-induced testis damage is rudimentary. In this investigation, we hypothesized that melatonin can minimize germ-cell depletion and morphological features of cell damage in testis following X-ray irradiation (XRI). To examine these effects, and to test our hypothesis, an animal model comprised of 60 Albino rats was established. The animals were divided into five groups: Group 1, non-irradiated; Group 2, X-ray irradiated (XRI, 8 Grays); Group 3, XRI pretreated with solvent (ethanol and phosphate-buffered saline); Group 4, non-irradiated group treated with melatonin and Group 5, XRI pretreated with melatonin. The testes were evaluated for both histological (light microscopy) and ultrastructural changes (transmission electron microscopy). Histologically, there were marked depletions (66%) of the germinal epithelial cells, in XRI group (Groups 2 and 3), whereas these changes were almost absent in XRI testis of animals pretreated with melatonin (Group 5). The number of spermatogenic cells in XRI testis of animals pretreated with melatonin (Group 5) was comparable (95%) to that of non-irradiated group (Groups 1 and 4) but significantly (P < 0.05) higher than those in XRI testis (34%, Groups 2 and 3). Ultrastructurally, XRI testis (Groups 2 and 3) showed features of apoptosis (condensation of the nuclei, vacuolization of the cytoplasm, increased cytoplasmic density and apoptotic bodies). These features were absent in XRI testis of animals pretreated with melatonin (Group 5). Also, this Group showed features of an increased metabolic activity (large acrosomal vesicle, prominent Golgi, increased mitotic activity, increased complement of cytoplasmic organelles and appearance of nucleoli-like bodies). There was a minimal depletion of the Sertoli and Leydig cells following XRI. Also, morphological features of apoptosis were infrequent in these cells. Administration of melatonin (MEL) prior to irradiation can protect testis against its destructive effects. The protective effects include amelioration of germ-cell depletion and apoptotic changes. The clinical ramifications of these observations mandate further studies.
辐射对生殖功能有深远影响。我们对褪黑素抗X射线诱导的睾丸损伤的辐射防护作用的了解还很初步。在本研究中，我们假设褪黑素可以使X射线照射（XRI）后睾丸中的生殖细胞耗竭和细胞损伤的形态特征最小化。为了研究这些影响并验证我们的假设，建立了一个由60只白化大鼠组成的动物模型。动物被分为五组：第1组，未照射组；第2组，X射线照射组（XRI，8格雷）；第3组，用溶剂（乙醇和磷酸盐缓冲盐水）预处理的XRI组；第4组，用褪黑素处理的未照射组；第5组，用褪黑素预处理的XRI组。对睾丸进行组织学（光学显微镜）和超微结构变化（透射电子显微镜）评估。组织学上，XRI组（第2组和第3组）的生精上皮细胞有明显耗竭（66%），而在用褪黑素预处理的动物的XRI睾丸中（第5组）几乎没有这些变化。在用褪黑素预处理的动物的XRI睾丸中（第5组）的生精细胞数量与未照射组（第1组和第4组）相当（95%），但显著高于（P<0.05）XRI睾丸中的数量（34%，第2组和第3组）。超微结构上，XRI睾丸（第2组和第3组）显示出凋亡特征（核浓缩、细胞质空泡化、细胞质密度增加和凋亡小体）。在用褪黑素预处理的动物的XRI睾丸中（第5组）没有这些特征。此外，该组显示出代谢活性增加的特征（大顶体泡、突出的高尔基体、有丝分裂活性增加、细胞质细胞器数量增加和核仁样体出现）。XRI后支持细胞和间质细胞的耗竭最小。此外，这些细胞中凋亡的形态特征很少见。照射前给予褪黑素（MEL）可以保护睾丸免受其破坏作用。保护作用包括改善生殖细胞耗竭和凋亡变化。这些观察结果的临床意义需要进一步研究。
