Prolonged and transient neonatal hypothyroidism on Leydig cell differentiation in the postnatal rat testis

Hypothyroidism arrests the differentiation of adult Leydig cells (ALC) in the neonatal rat testis, and transient neonatal hypothyroidism produces a two-fold increase in the ALC numbers in the adult rat testis. We investigated 1) whether prolonged hypothyroidism beyond the neonatal period could continue to arrest the differentiation of the ALC, and 2) to understand how a two-fold increase in the number of ALC is produced in adult rats subjected to transient neonatal hypothyroidism. Three groups of Sprague Dawley rats were used; control, PTU-water group (transiently hypothyroid; added 0.1% propyl thiouracil/PTU to drinking water of lactating mothers at parturition until weaning of pups at day 21, pups were fed regular water thereafter), and PTU group (prolonged hypothyroid; mothers were fed 0.1% PTU in drinking water from parturition until pups were sacrificed at days 28 and 40 (pups had access to solid food after 21 days). Findings showed that PTU treatment continued to arrest ALC differentiation. Withdrawal of the PTU treatment at 21 days resulted in ALC differentiation by two-fold in number in PTU-water rats. Findings on luteinizing hormone (LH)-stimulated androgen secretory capacity per testis in vitro agreed with the morphological data. These results confirmed that 1) thyroid hormone is crucial to the onset of ALC differentiation in the postnatal rat testis, 2) increased numbers of mesenchymal cells present in the hypothyroid testes differentiate into ALC upon withdrawal of the PTU treatment to produce a two-fold number of ALC in adult rats subjected to transient neonatal hypothyroidism (i.e., PTU-water treatment), and 3) numbers of ALC and mesenchymal cells increase with age at a rate of 2:1 during the process of ALC differentiation in testes of control and PTU-water rats.     

Transgenerational effect of the endocrine disruptor vinclozolin on male spermatogenesis

The current study was designed to examine the actions of a model endocrine disruptor on embryonic testis development and male fertility. Pregnant rats (F0) that received a transient embryonic exposure to an environmental endocrine disruptor, vinclozolin, had male offspring (F1) with reduced spermatogenic capacity. The reduced spermatogenetic capacity observed in the F1 male offspring was transmitted to the subsequent generations (F2-F4). The administration of vinclozolin, an androgen receptor antagonist, at 100 mg/kg/day from embryonic day 8-14 (E8-E14) of pregnancy to only the F0 dam resulted in a transgenerational phenotype in the subsequent male offspring in the F1-F4 generations. The litter size and male/female sex ratios were similar in controls and the vinclozolin generations. The average testes/body weight index of the postnatal day 60 (P60) males was not significantly different in the vinclozolin-treated generations compared to the controls. However, the testicular spermatid number, as well as the epididymal sperm number and motility, were significantly reduced in the vinclozolin generations compared to the control animals. Postnatal day 20 (P20) testis from the vinclozolin F2 generation had no morphological abnormalities, but did have an increase in spermatogenic cell apoptosis. Although the P60 testis morphology was predominantly normal, the germ cell apoptosis was significantly increased in the testes cross sections of animals from the vinclozolin generations. The increase in apoptosis was stage-specific in the testis, with tubules at stages IX-XIV having the highest increase in apoptotic germ cells. The tubules at stages I-V also had an increase in apoptotic germ cells compared to the control samples, but tubules at stages VI-VIII had no increase in apoptotic germ cells. An outcross of a vinclozolin generation male with a wild-type female demonstrated that the reduced spermatogenic cell phenotype was transmitted through the male germ line. An outcross with a vinclozolin generation female with a wild-type male had no phenotype. A similar phenotype was observed in outbred Sprague Dawley and inbred Fisher rat strains. Observations demonstrate that a transient exposure at the time of male sex determination to the antiandrogenic endocrine disruptor vinclozolin can induce an apparent epigenetic transgenerational phenotype with reduced spermatogenic capacity.     

Gestational exposure to atrazine: effects on the postnatal development of male offspring

Atrazine is an herbicide used worldwide to control grasses and weeds. Previous studies have shown that, depending on atrazine's administered dose, exposure of male rats during the early postnatal or peripubertal periods can result in alterations in endocrine function. The gestational period is particularly vulnerable to environmental agents; however, the possible effects of atrazine exposure during this period have received only limited attention. Herein we examine the dose effects of atrazine exposure during Sprague-Dawley rat gestation on the postnatal development of male offspring. Pregnant dams were treated by oral gavage with atrazine at 0 to 100 mg/kg/d from gestational day 14 to parturition. Thereafter, neither the pups nor the dams received atrazine. Atrazine had no effect on the number of live births per dam. Neonatal pup survival was affected, however, with increased pup death seen at doses of 10 mg/kg/d and higher. There was no effect of atrazine on the testosterone concentration within the testes of newborn pups. Anogenital distance, an androgen-dependent process, decreased from the control level at the 75 and 100 mg/kg/d doses, with the decrease reaching significance at 100 mg/kg/d. Preputial separation, also an androgen-dependent process, was delayed significantly compared with that in controls in response to the 50 and 100 mg/kg/d doses. At postnatal day 60, serum testosterone concentrations were reduced significantly from controls in the 50 to 100 mg/kg/d groups. However, these decreases had little effect on seminal vesicle or ventral prostate weights. These results, taken together, are suggestive of antiandrogenic effects of gestational atrazine exposure on male offspring, although for most parameters, the doses used in this study are unlikely to be experienced under any but experimental conditions.     

青春期己烯雌酚暴露对大鼠睾丸发育及功能的影响

目的 探讨青春期己烯雌酚(diethylstilbestrol,DES)暴露对SD(Sprague-Dawley)大鼠睾丸发育及功能的影响.方法 35日龄雄性SD大鼠90只,随机分为DES 0.01、0.1、1.0、10.0 μg·kg-1·d-14个实验组和1个对照组(编码为Bda、BDb、BDc、BDd和BC组,每组18只).于青春期,即出生后第36天(postnatal day 36,PND 36)至PND 49,实验组每日皮下注射相应剂量的DES,共14 d,对照组仅注射溶媒.于青春期晚期(PND 50)、性成熟后(PND 64)和成年期(PND 130)分3批(每批6只)处死各组大鼠取材,测定睾丸重量,观察比较睾丸组织形态学变化,分析PND 130大鼠附睾尾精子质量.结果 PND 50时,BC、Bda、BDb、BDc和BDd组单侧睾丸重量分别为(1.26±0.13)、(1.23±0.20)、(0.99±0.15)、(0.85±0.23)和(0.60±0.04)g,其中BDb、BDc和BDd组均较BC组减轻(P＜0.05);与BC组比较,BDb组仅有少数生精小管生精上皮中的细胞数目稍减少,BDc和BDd组生精小管发育较差、生精上皮中细胞数目减少、精子发生阻滞、间质细胞发育幼稚,其程度随DES暴露剂量增加而加重.PND 64时,BC、Bda、BDb、BDc和BDd组单侧睾丸重量分别为(1.54±0.14)、(1.55±0.17)、(1.52±0.11)、(1.37±0.14)和(0.88±0.15)g,其中BDc和BDd组均较BC组减轻(P＜0.05);BDc和BDd组睾丸组织形态学改变与PND 50时类似,但较PND 50时有所改善.PND 130时,各实验组与对照组比较,单侧睾丸重量差异无统计学意义(P＞0.05),睾丸组织形态学改变未见明显差异;BC、Bda、BDb、BDc和BDd组大鼠附睾尾精子密度分别为(71.00±14.85)、(69.00±23.98)、(67.00±13.52)、(31.67±12.94)和(18.83±6.68)×106/ml,其中BDc和BDd组精子密度均较BC组明显降低(P＜0.01);与BC组比较,BDd组精子活动率下降(P＜0.01),BDb、BDc和BDd组A级精子比例降低(P＜0.05),BDd组B级精子比例降低(P＜0.01).结论 青春期小剂量DES(0.01μg·kg-1·d-1×14 d)暴露对SD大鼠睾丸发育及功能无明显影响,大剂量DES(1.0～10.0 μg·kg-1·d-1×14 d)暴露对大鼠睾丸发育及功能具有明显的近期(PND 50和PND 64)和较远期(PND 130)毒性作用,该毒性作用随DES暴露剂量增加而加重,随鼠龄增长而逐渐减退,其机制可能与间质细胞和支持细胞的发育及功能受损密切相关.     

Spatiotemporal expression patterns of natriuretic peptides in rat testis and epididymis during postnatal development

Natriuretic peptide (NP) family is composed of atrial, brain and C‐type NP (NPPA, NPPB and NPPC). Here, we aimed to investigate NP expression in testis and epididymis during postnatal development. NPPA expression was observed in gonocytes at prepubertal period but in only spermatocytes in pachytene and leptotene/zygotene stage at pubertal period. In prepubertal and pubertal periods, we detected NPPB expression in only Leydig cells. However, NPPC expression was detected in all of the gonocytes and Sertoli cells, spermatocytes and some interstitial cells in prepubertal and pubertal periods. In postpubertal and mature periods, NPPA and NPPB staining were detected in Leydig cells, elongated and round spermatids but not in spermatogonia and spermatocytes. However, we observed NPPC expression in all cells of the seminiferous tubules and Leydig cells in the postpubertal and mature periods. Epididymal epithelium showed intense NPPC expression during postnatal period but weak NPPA and NPPB expression in prepubertal and pubertal periods. The expression of three NPs in the testis significantly increased after puberty. In conclusion, puberty had a significant effect on NP expression in testis. Unlike NPPA and NPPB, expression of NPPC in all cells of the seminiferous tubule suggests that NPPC is effective in each step of spermatogenesis.     

Expression profile of Toll-like receptor 4 in rat testis and epididymis throughout postnatal development

Toll-like receptors (TLRs) belonging to pattern recognition receptors are involved in maintaining testicular and epididymal immune homeostasis. The purpose of the current study was to investigate TLR4 expression in rat testis and epididymis throughout postnatal development. Weak staining was detected in peritubular myoid cells and immature Sertoli cells while no staining was observed in gonocytes during prepubertal period. However, TLR4 expression began to appear in spermatocytes in pubertal period and gradually increased in spermatids. An intense staining was observed in steps 5–19 spermatids in post pubertal and mature periods. Similarly, TLR4 expression in the testes steadily increased from pubertal period to mature period. Puberty also caused a significant increase in TLR4 expression in epididymis. TLR4 expression in cauda epididymis was lower as compared to those of other epididymal segments. The majority of epididymal epithelial cells exhibited apical TLR4 expression, whereas basal cells showed intense intracytoplasmic immunoreaction. We detected an intense staining in epididymal smooth muscle cells. The expression levels of TLR4 showed dynamic changes in both spermatogenic cells, and entire testicular and epididymal tissues during postnatal development. These results suggest that TLR4 expression contributes not only to inflammation but also to the development of spermatogenic cells.     

雌二醇对大鼠睾丸组织生长发育的影响

目的　研究雌二醇对睾丸组织生长发育的影响及作用机理。方法　以雄性幼年SD大鼠为对象,设实验组和对照组,实验组大鼠皮下注射苯甲酸雌二醇(E2B,0.04mg/g体重),于注药后第14、28、42、56天取材。行睾丸重量测定、组织病理学观察和凝集素(ConA,GS-I,PNA,SBA和DBA)组织化学实验。结果　实验组睾丸重量(1×10     

Immunolocalisation and expression of Smad2 and Smad4 proteins in dog testis during postnatal development

The expression and localisation of downstream signalling molecules of transforming growth factor beta superfamily, Smad2 and Smad4 proteins, was investigated in immature and mature dog testis. Cellular localisation of Smad2 and Smad4 proteins was examined using immunohistochemistry. Quantitative analysis of immunostaining was determined by the image analysis system. The specificity of the antibodies was examined using Western blotting assay. Smad2 and Smad4 were widely expressed in the testes, mainly immunolocalised in the cytoplasm of gonocytes, Leydig cells and Sertoli cells of immature testes, and Leydig cells and Sertoli cells of mature testes. At the same time, the expression levels for both proteins were different between immature and mature age groups: the expression of Smad2 and Smad4 proteins in the Sertoli cells of mature testis was higher than in the immature group (P < 0.05), but the expression of these two proteins in Leydig cells of mature testis was weaker than that seen in immature stage (P < 0.05). The temporospatial distribution of Smad2 and Smad4 proteins in testicular cells suggests that these two signalling molecules may play an important role in specific stages of testicular development and spermatogenesis, thus providing direct evidences for transforming growth factor beta action in the dog testis.     

Glucocorticoid receptor distribution in rat testis during postnatal development and effects of dexamethasone on immature peritubular cells in vitro

In this study, the occurrence of the glucocorticoid receptor in the rat testis during early stages of postnatal development and its potential functional significance were investigated. Quantitative analyses of immunohistochemically labelled paraffin sections revealed that the receptor was present during all stages of postnatal development in the nuclei of interstitial cells such as Leydig cells, macrophages and fibroblasts, and endothelial cells of blood vessels. The labelling index increased initially, with maximum levels reached within the second week of postnatal development, and decreased thereafter. Within the seminiferous tubules, the glucocorticoid receptor could be detected in the nuclei of germ cells as well as Sertoli cells, reaching the highest levels in 3-week-old rats, mainly due to immature germ cell staining. In contrast, approximately 50% of the peritubular cell nuclei were stained throughout postnatal development. In vitro experiments on immature and immortalized peritubular cells demonstrated a dose-dependent and significant decrease in proliferation and fibronectin secretion after administration of dexamethasone. The data of this study suggest that glucocorticoids have a consistently repressive effect on peritubular cells throughout postnatal development. In summary, labelling of germ cells, especially in immature rats, might indicate an inhibition of spermatogenesis by corticosteroids.     

联合内分泌治疗对前列腺和睾丸的影响

目的 探讨抑那通和缓退瘤联合治疗对正常前列腺,增生的前列腺（ＢＰＨ）和前列腺癌以及睾丸的作用。方法 对１６例接受联合内分泌治疗至少３个月且有治疗前后病理资料的前列腺癌患者的标本进行了系统的病理学检查。对内分泌治疗后的睾丸标本与同龄未接受治疗的进行对照研究。结果 １４例内分泌治疗后的前列腺标本２例未见残存癌灶,９例对治疗有明显的反应;３例对治疗反应差,治疗并未降低前列腺癌的病理分期。３例内分泌治疗后     

胚胎发育时期接触过乙酸羟孕酮的成年雄性大鼠的肝脏代谢改变(英文)

目的:观察胚胎在子宫内接触乙酸羟孕酮对雄性大鼠成年后肝脏代谢的影响。方法:让怀孕1天、7天和14天的 Wistar 白化大鼠分别接触高于正常浓度的乙酸羟孕酮(10 mg/kg 和25 mg/kg)。出生的雄性仔鼠在可控条件下喂养,出生90天后处死,迅速切取肝脏组织称重,并用于生化分析。结果:胚胎发育时期接触过乙酸羟孕酮的大鼠肝脏中的琥珀酸酯脱氢酶、谷氨酸酯脱氢酶、葡萄糖-6-磷酸盐脱氢酶、苹果酸酯脱氢酶以及转氨酶(aminotransaminases)的活性显著提高,乳酸脱氢酶的活性显著下降。此外,与对照组相比,随着实验大鼠肝脏组织脂质氧化反应的增加,抗氧化酶(谷胱甘肽 S 型转移酶和过氧化氢酶)活性也有显著增加。结论:上述实验结果表明胚胎发育时期接触过乙酸羟孕酮的大鼠的氧化代谢、抗氧化机制以及脂质过氧化水平都得到了提高。转氨酶活性的增加表明线粒体的完整性被损伤和破坏。     

CatSperl在小鼠睾丸发育过程中的动态表达及与人精子活力的关系

目的 研究CatSper1 mRNA在小鼠睾丸发育过程中的动态变化，并探讨CatSper1蛋白表达与精子运动的关系。方法 采用荧光实时逆转录多聚酶链反应（RT-PCR）相对定量法检测CatSper1mRNA在出生后11、15、18、21、25、28、35、42、56和120d龄C57BL／6小鼠（每天龄3只）睾丸中的表达；分别从4例正常精液标本中用四层密度梯度Percoll（浓度分别为95％、76％、57％和47．5％）离心分离出高活力和低活力精子，用于Western Blot定量检测CatSper1蛋白的表达。结果CatSper1mRNA在18d龄小鼠睾丸开始表达，在25和28d龄表达上调明显，分别为21d龄表达水平的2．95和7．59倍。自42d后上调缓慢，至成年小鼠时达到最高水平。CatSper1蛋白在每例标本高活力精子中的表达量均显著高于低活力精子（P〈0．05）。结论 CatSper1与精子活力特性有关，为进一步研究CatSper家族各成员间的关系和确切功能提供参考依据。     

甲氧滴滴涕对雄性大鼠生精细胞的细胞周期影响

目的探讨甲氧滴滴涕(MXC)对雄性大鼠生精细胞的细胞周期影响。方法实验动物分为对照组,溶剂组,5 d、10 d和15 d MXC实验组。用流式细胞仪检测染毒雄性大鼠生精细胞周期变化。结果随着MXC染毒时间延长与对照组比较,实验组G0/G1期与S期细胞数减少,G2/M期细胞数增多(P<0.05),单倍体细胞减少,二倍体与四倍体细胞增多(P<0.05);除5 d实验组二倍体与四倍体细胞荧光强度强外,其余各实验组的单倍体、二倍体和四倍体细胞荧光强度均减弱(P<0.05);溶剂组与对照组间的变化无显著性差异(P>0.05)。结论MXC可引起大鼠睾丸生精细胞S期抑制及G2期阻滞。     

Expression and localization of Smadl, Smad2 and Smad4 proteins in rat testis during postnatal development

Aim: To study the expression and regulation of Smadl, Smad2 and Smad4 proteins (intracellular signaling molecules of transforming growth factor-β family) in rat testis during postnatal development. Methods: The whole testes were collected from SD rats aged 3, 7, 14, 28 and 90 (adult) days. The cellular localization and developmental changes were examined by immunohistochemistry ABC method with the glucose oxidase-DAB-nickel enhancement technique. Quantitative analysis of the immunostaining was made by the image analysis system. The Smads proteins coexistence in the adult rat testis was tested by the double immune staining for CD14-Smad4 and Smad2-Smad4. The protein expression of Smad during rat testicular development was examined by means of Western blots. Results: Smadl, Smad2 and Smad4 were present throughout testicular development. The immunostaining of Smadl and Smad2 were present in spermatogenic cells. A positive immunoreactivity was located at the cytoplasm, but the nucleus was negative. Smadl wa