泛素碳端水解酶L1在邻苯二甲酸二丁酯诱导大鼠睾丸发育异常中的表达变化

目的:利用邻苯二甲酸二丁酯(DBP)诱导大鼠睾丸发育异常,验证泛素碳端水解酶L1(UCHL1)在异常睾丸与正常大鼠睾丸中的差异表达,以进一步探讨UCHL1在DBP导致的大鼠睾丸发育异常中的作用机制。方法:孕SD大鼠40只,妊娠14~18d,随机分为2组,实验组和对照组分别予DBP 800mg/(kg·d)、大豆油5ml/d灌胃,孕期第19d(GD19)和出生后22d(PND22),分别取胎鼠及仔鼠睾丸,定量定位分析UCHL1在胎鼠及仔鼠睾丸中的表达变化。结果:GD19,UCHL1在实验组的相对表达量为0.075±0.02(n=10),对照组为0.150±0.02(n=10),2组差异有显著性(P<0.05),UCHL1在实验组中比正常对照组下降50%;而PND22,UCHL1于实验组隐睾睾丸中的相对表达量为0.344±0.03(n=10),实验组非隐睾睾丸中为0.326±0.02(n=10),对照组为0.322±0.02(n=10),3组间无明显统计学差异(P>0.05)。UCHL1主要定位于睾丸发育时期的精原细胞,初级精母细胞和次级精母细胞的胞质与胞核中。结论:DBP在染毒期间影响了睾丸生精细胞UCHL1的表达,影响了泛素-蛋白酶体系的平衡,从而导致生精小管的变薄,各层生精细胞数目减少的睾丸发育异常现象。     

Cellular origins of testicular dysgenesis in rats exposed in utero to di(n-butyl) phthalate

Foetal exposure of male rats to di(n-butyl) phthalate (DBP) induces testicular changes similar to testicular dysgenesis syndrome in humans, including the formation of focal 'dysgenetic areas' within post-natal testes, surrounded by otherwise normal tubules exhibiting complete spermatogenesis. We hypothesize that these dysgenetic areas form when Sertoli (and other) cells are 'trapped' during the abnormal formation of large Leydig cell (LC) clusters in foetal life and by post-natal day (d) 4 these groups of intermingled cells attempt to form seminiferous tubules. It is likely that the malformed tubules resulting correspond to the dysgenetic areas evident in later life. This also provides a plausible explanation for the occurrence of LCs within seminiferous cords/tubules in or bordering the dysgenetic areas. In our previous studies intratubular LCs (ITLCs) were identified by immunostaining for 3beta-hydroxysteroid dehydrogenase (3beta-HSD), the definitive LC cytoplasmic marker. However, the possibility remained that the 'presumptive' ITLCs were in fact Sertoli cells that had aberrantly gained the ability to express 3beta-HSD. Therefore, the aim of the present study was to fully characterize the ITLCs induced by in utero DBP exposure in d25 rats using a number of LC- (3beta-HSD, P450 side-chain cleavage enzyme, insulin-like factor 3, oestrogen receptor alpha) and Sertoli cell- (vimentin, Wilm's tumour-1) specific markers. Our results show that ITLCs express all four LC-specific markers but do not express either of the Sertoli cell markers. It is therefore concluded that the ITLCs are bona fide LCs that are abnormally located within the seminiferous tubules of DBP-exposed rats in post-natal life.     

邻苯二甲酸二乙基己酯对新生小鼠睾丸及Leydig细胞影响的实验研究

目的:探讨邻苯二甲酸二乙基己酯(DEHP)对新生小鼠睾丸及Leyd ig细胞形态结构及功能的影响。方法:DEHP分别以低、中、高3组剂量[100、200、500 mg/(kg.d)]灌胃作用于怀孕12 d到产后3 d(GD12~PND3)的KM母鼠,观察DEHP对新生雄性仔鼠体重、睾丸重量、Leyd ig细胞形态结构和3β-羟基类固醇脱氢酶(3-βHSD)活性、酶反应面积的影响。结果:DEHP作用于母鼠后,其雄性子代幼鼠体重和睾丸重量减轻,睾丸Leyd ig细胞形态、超微结构发生改变;高剂量组Leyd ig细胞数量明显增多;低、中剂量组睾酮合成关键酶3β-HSD酶活性下降,酶反应面积减小,但高剂量组在仔鼠出生后15 d时酶活性降低[(吸光度值(0.154±0.011)vs空白对照组(0.222±0.013),P<0.01],而酶反应面积增大[(6 303.0±745.6)μm2vs空白对照组(5 091.4±214.4)μm2,P<0.01)]。结论:DEHP能影响新生雄性小鼠体重、睾丸重量、Leyd ig细胞的形态结构和3β-HSD活性,具有抗雄激素效应。     

邻苯二甲酸二(2-乙基)己酯对小鼠胎鼠睾丸及睾丸引带的影响

目的:研究邻苯二甲酸二(2-乙基)己酯(DEHP)对小鼠胎鼠睾丸与睾丸引带形态结构及功能的影响,探讨隐睾发生的可能机制。方法:30只健康KM孕鼠随机均分为3组:空白对照组、玉米油对照组、DEHP组。DEHP组以剂量500mg/(kg.d)的DEHP灌胃作用于怀孕12～19d(GD12～GD19)的KM母鼠,观察DEHP对每胎胎鼠数、雌雄性胎鼠比例、雄性胎鼠体重、睾丸重量、睾丸引带形态结构、位置、睾丸到膀胱颈之间的相对距离(TBD)、颅侧悬韧带残留情况、引带内雄激素受体(AR)、雌激素受体(ER)、肌动蛋白、增殖细胞核抗原(PCNA)表达水平的影响。结果:DEHP对每胎胎鼠数、雌雄性胎鼠比例、雄性胎鼠体重无明显影响;DEHP可影响胎鼠睾丸重量及TBD;DEHP组睾丸均有一定程度的下降不全,睾丸引带形态结构无明显差异;光镜下见DEHP组睾丸生精小管、支持细胞存在明显的发育障碍,睾丸Leydig细胞明显增生;DEHP组睾丸引带AR阳性表达率降低(P<0.01)。结论:DEHP可通过抗雄激素效应导致睾丸引带功能障碍,使睾丸下降发生异常而诱导小鼠隐睾;同时造成睾丸Ser-toli细胞、睾丸Leydig细胞和生精细胞的发育障碍和功能改变。     

Disruption of reproductive development in male rat offspring following in utero exposure to phthalate esters

Certain Phthalate esters have been shown to produce reproductive toxicity in male rodents with an age dependent sensitivity in effects with foetal animals being more sensitive than neonates which are in turn more sensitive than pubertal and adult animals. While the testicular effects of phthalates in rats have been known for more than 30 years, recent attention has been focused on the ability of these agents to produce effects on reproductive development in male offspring after in utero exposure. These esters and in particular di-butyl, di-(2-ethylhexyl) and butyl benzyl phthalates have been shown to produce a syndrome of reproductive abnormalities characterized by malformations of the epididymis, vas deferens, seminal vesicles, prostate, external genitalia (hypospadias), cryptorchidism and testicular injury together with permanent changes (feminization) in the retention of nipples/areolae (sexually dimorphic structures in rodents) and demasculinization of the growth of the perineum resulting in a reduced anogenital distance (AGD). Critical to the induction of these effects is a marked reduction in foetal testicular testosterone production at the critical window for the development of the reproductive tract normally under androgen control. A second Leydig cell product, insl3, is also significantly down regulated and is likely responsible for the cryptorchidism commonly seen in these phthalate-treated animals. The testosterone decrease is mediated by changes in gene expression of a number of enzymes and transport proteins involved in normal testosterone biosynthesis and transport in the foetal Leydig cell. Alterations in the foetal seminiferous cords are also noted after in utero phthalate treatment with the induction of multinucleate gonocytes that contribute to lowered spermatocyte numbers in postnatal animals. The phthalate syndrome of effects on reproductive development has parallels with the reported human testicular dysgenesis syndrome, although no cause and effect relationship exists after exposure of humans to phthalate esters. However humans are exposed to and produce the critical phthalate metabolites that have been detected in blood of the general population, in children and also human amniotic fluid.     

青春期前邻苯二甲酸二丁酯持续暴露对大鼠睾丸发育的影响

目的:研究青春期前邻苯二甲酸二丁酯(DBP)持续暴露对睾丸发育的影响。方法:21日龄断乳青春期前雄性SD大鼠随机分为对照组(n=24)和实验组(n=54),每日分别用玉米油或DBP玉米油溶液灌胃,DBP暴露剂量分别为50mg/(kg.d)(低剂量组,n=18)、200mg/(kg.d)(中剂量组,n=18)和600mg/(kg.d)(高剂量组,n=18),各组动物持续暴露14、21、28d后(即PND35,PND42和PND49)断颈处死。记录大鼠体重变化,检测睾丸重量和体积、附属性器官重量及附睾精子,化学发光免疫分析法检测血清睾酮含量,苏木精-伊红染色观察睾丸组织形态学变化,测量生精小管平均直径及进行睾丸活检评分。结果:低剂量组PND35少量生精小管生精细胞排列紊乱,PND42和PND49睾丸、附属性器官发育及生精功能正常;中剂量组PND35和PND42生精细胞排列紊乱、数目减少,PND49生精小管内可见各级生精细胞及精子,睾丸未见萎缩,附属性器官发育正常;高剂量组大鼠体重增长减缓,血清睾酮水平低下,睾丸生精小管变性萎缩,生精上皮发育阻滞,生精细胞大量凋亡坏死,青春期大鼠睾丸萎缩,无精子,附睾、前列腺和精囊等附属性器官发育迟缓。结论:青春期前DBP持续暴露可损害睾丸组织发育和正常生精功能形成,其毒性效应具有剂量依赖性,高剂量DBP持续暴露引起的睾丸毒性在青春期前发育过程中不可修复,而低中剂量暴露引起的睾丸毒性在PND49之前可完全或部分逆转性恢复。     

The effects of maternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin on testicular steroidogenesis in infantile male rats

Exposure of adult male animals to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) decreases serum androgen concentrations. Reduction in androgen levels after maternal exposure has also been reported, but these results have not been reproduced. We have earlier shown that TCDD stimulates rather than inhibits testosterone synthesis in the prenatal rat testis. The aim of the present study was to elucidate in utero-induced effects of TCDD on testicular steroidogenesis in the 14-day-old infant rats. At that time the foetal Leydig cell population is still the prevailing source of androgens. Pregnant Sprague-Dawley dams were given a single oral dose of TCDD (0, 0.04, 0.2, or 1.0 microg/kg) on day 13 of pregnancy. On postnatal day 14, the body weight of male offspring was reduced after exposure to 1.0 microg/kg TCDD (from 33.9 +/- 1.66 g to 31.6 +/- 2.67 g). Relative testis weight, plasma testosterone, luteinizing hormone and follicle-stimulating hormone levels remained unaltered in all exposure groups. Moreover, in ex vivo incubations, testosterone and cAMP production was not affected. StAR protein level in the freshly isolated testes was increased in the 0.2 microg/kg group, and seminiferous cord diameter in the 0.04 microg/kg group. The present study confirms our earlier findings in in utero TCDD-exposed foetal testis indicating that maternal TCDD exposure does not negatively influence the developmental testosterone production of foetal type Leydig cells in rats.     

The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on foetal male rat steroidogenesis

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic and widely investigated dioxin congener. In utero and lactational exposure to TCDD results in developmental and reproductive defects that are the most sensitive endpoints for TCDD toxicity. TCDD has a potential to interfere with steroid metabolism, but the mechanisms by which this occurs are not well understood. In this study, we investigated the effects of TCDD on prenatal rat steroidogenesis. Pregnant Sprague-Dawley female rats were treated once with TCDD (0, 0.3 or 1 microg/kg) by gavage on embryonic day (ED) 11 and the expression levels of androgen (AR) and estrogen receptors (ER), steroidogenic enzymes (P450scc and 3beta-HSD) and four regulatory factors (StAR, SF-1, GATA-4 and Insl-3) involved in foetal Leydig cell and adrenal function were analysed on ED 19.5. Hormonal status of male foetuses was determined by measuring testicular testosterone (T) levels, plasma luteinizing hormone (LH) and corticosterone concentrations. In utero exposure to TCDD reduced intratesticular T of foetal males (significant at 0.3 microg/kg TCDD) and tended to reduce the protein expression of ERalpha and AR of foetal male rat testis. Foetal male rat plasma LH levels were significantly reduced at the dose of 1 microg/kg TCDD, while corticosterone levels tended to be increased possibly because of the TCDD-induced stress. Only minor alterations in steroidogenesis were observed in rat adrenal. mRNA expression of developmental regulatory factors was not influenced by foetal TCDD exposure, except for significantly reduced adrenal SF-1. The results demonstrate that maternal exposure to TCDD suppressed testicular steroidogenesis of 19.5-day-old foetal male Sprague-Dawley rat. The highest dose of TCDD (1 microg/kg) had also an effect on pituitary LH secretion. Our data implicate that TCDD has direct testicular and pituitary effects on foetal male rat but with different dose-responses. These changes can lead to impaired steroidogenesis and it may result in the maldevelopment of the testis and weaken masculinization.     

邻苯二甲酸二-(2-乙基)己酯致小鼠隐睾睾丸和附睾的组织病理学改变

目的 :探讨邻苯二甲酸二 (2 乙基 )己酯 (DEHP)引起的小鼠隐睾睾丸和附睾的组织病理学改变。　方法 :妊娠KM小鼠 4 0只 ,随机分成 5组 ,分别为正常对照组 8只、玉米油对照组 8只、己烯雌酚 (DES)组 8只、DEHP低剂量组 [DEHP 10 0mg/ (kg·d) ]9只和DEHP高剂量组 [DEHP 5 0 0mg/ (kg·d) ]7只。自妊娠第 12d开始到分娩后 3d ,分别持续经口给予DEHP 10 0mg/ (kg·d)、5 0 0mg/ (kg·d)和DES 10 0 μg/ (kg·d)及玉米油 ,观察仔代雄小鼠的隐睾发生率及隐睾睾丸和附睾的组织病理学改变。　结果 :DEHP 5 0 0mg/ (kg·d)组染毒小鼠的隐睾发生率显著增高 ,睾丸和附睾的体积明显减小、重量减轻 ;睾丸生精上皮发育明显异常 ,精曲小管变薄、萎缩 ,间质细胞异常增生 ,电镜下其隐睾精曲小管上皮和间质细胞均出现明显的超微结构改变。同时附睾管腔中的精子数显著减少甚至缺乏。　结论 :高剂量 [5 0 0mg/ (kg·d) ]DEHP可能具有与DES类似的作用 ,是一种诱发隐睾的重要因子。小鼠在孕期及哺乳期接触DEHP后可引起雄性仔鼠性分化异常 ,诱导隐睾发生、睾丸生精上皮损害和生精过程障碍 ,从而对雄性仔鼠生育力产生不利影响。以上作用存在明确的量 效关系。     

The origins and time of appearance of focal testicular dysgenesis in an animal model of testicular dysgenesis syndrome: evidence for delayed testis development?

A testicular dysgenesis-like syndrome is induced in rats by fetal exposure to di(n-butyl) phthalate (DBP). A key feature of this is the formation of focal dysgenetic areas comprising malformed seminiferous cords/tubules and intratubular Leydig cells (ITLC), but how and why these arise remains unclear. The present study has used combinations of cell-specific markers and immunohistochemistry to address this. The results show that focal dysgenetic areas and ITLC first appear postnatally at 4-10 days of age, but this only occurs in treatment groups in which formation of fetal Leydig cell aggregation is induced between e17.5 and e21.5. Extreme variability in the formation and size of the Leydig cell aggregates probably accounts for the equally extreme variation in occurrence and size of focal dysgenetic areas postnatally. DBP-induced fetal Leydig cell aggregation traps Sertoli and other cells within the aggregates, but it is unclear why this happens nor why cords fail to form prenatally in these cell mixtures but do elsewhere in the fetal testis. The present studies show that differentiation of the fetal Leydig cells is drastically delayed at e15.5 after DBP exposure, which may be indicative of a wider delay in testis cell development and organisation, and this might account for some of the unexplained findings.     

Chlormadinone acetate pellet implantation plus short-term oral administration in dogs with benign prostatic hypertrophy

Eight beagles with benign prostatic hypertrophy (BPH) were treated by subcutaneous implantation of pellets containing 10 mg/kg chlormadinone acetate (CMA), a synthetic anti-androgen, plus daily oral administration of CMA at 2 mg/kg per day for 7 days as a therapy for BPH. Prostatic and testicular size were measured and prostatic and testicular biopsies were performed by laparotomy before and after CMA treatment. Plasma levels of luteininzing hormone (LH), testosterone and oestradiol were also measured. The clinical signs of BPH, for example haematuria and dysuria, resolved within 1 week of treatment. Mean prostatic volume decreased to 56% of the pretreatment value. At 40 weeks after treatment, prostatic volume had decreased by 36%. Histological examination of the prostate 1 week after treatment revealed reduction in diameter of the alveoli and in height of the glandular epithelium. Degeneration and atrophy of the glands were marked 4–12 weeks after treatment. In the testis, the diameter of seminiferous tubules and the number of germ cells in the seminiferous tubules had decreased markedly at 12 and 24 weeks after treatment. Although plasma LH concentrations did not undergo any marked fluctuations after CMA treatment, levels of testosterone and oestradiol were lower than before treatment. The results indicate that implantation of 10 mg/kg CMA, plus 7-day oral administration of 2 mg/kg CMA, bring about resolution of the clinical signs and marked reduction in prostatic volume within 1 week of treatment.     

Induction and persistence of abnormal testicular germ cells following gestational exposure to di-(n-butyl) phthalate in p53-null mice

Phthalate esters are commonly used plasticizers found in many household items, personal care products, and medical devices. Animal studies have shown that in utero exposure to di-(n-butyl) phthalate (DBP) within a critical window during gestation causes male reproductive tract abnormalities resembling testicular dysgenesis syndrome. Our studies utilized p53-deficient mice for their ability to display greater resistance to apoptosis during development. This model was chosen to determine whether multinucleated germ cells (MNG) induced by gestational DBP exposure could survive postnatally and evolve into testicular germ cell cancer. Pregnant dams were exposed to DBP (500 mg/kg/day) by oral gavage from gestational day 12 until birth. Perinatal effects were assessed on gestational day 19 and postnatal days 1, 4, 7, and 10 for the number of MNGs present in control and DBP-treated p53-heterozygous and null animals. As expected, DBP exposure induced MNGs, with greater numbers found in p53-null mice. Additionally, there was a time-dependent decrease in the incidence of MNGs during the early postnatal period. Histologic examination of adult mice exposed in utero to DBP revealed persistence of abnormal germ cells only in DBP-treated p53-null mice, not in p53-heterozygous or wild-type mice. Immunohistochemical staining of perinatal MNGs and adult abnormal germ cells was negative for both octamer-binding protein 3/4 and placental alkaline phosphatase. This unique model identified a role for p53 in the perinatal apoptosis of DBP-induced MNGs and provided insight into the long-term effects of gestational DBP exposure within a p53-null environment.     

Maternal CBZ exposure impairs testicular development,spermatogenesis and sperm parameters in male offspring at puberty

Carbamazepine (CBZ), an anticonvulsant drug, is used by pregnant women and crosses the placental barrier, reaching the embryo/foetus. CBZ inhibits testicular steroidogenesis and may lead to alterations in testicular development, spermatogenesis and male fertility. The purpose of this study was to evaluate the CBZ effects on testicular parameters in the neonatal and pubertal phases, as well as the spermatic parameters of pubertal rats, originated from dams treated during different periods of the pregnancy. Pregnant rats were treated with CBZ (20 mg/kg/day; intraperitoneal route), from 12–20 gestation day (GD) (CBZ12 group) and 15–20 GD (CBZ15 group). The testicular morphometric and stereological analysis of rats aged 4 and 63 days was performed. The oestradiol and testosterone plasmatic levels, as well as spermatic parameters, were achieved at 63 days. CBZ12 group showed a reduction in testicular weight and volume at 4 days post-partum (dpp); however, there was an increase in the seminiferous cords’ length of the CBZ12 and CBZ15 groups. At 63 days, the CBZ12 group showed increases of the daily sperm production and damage in the seminiferous epithelium. The results suggest that CBZ interferes with the testis development and the establishment of the spermatogenic process, which can be detected in the puberty phase.     

Short-term effects of di-（2-ethylhexyl） phthalate on testes,liver, kidneys and pancreas in mice

Aim： To determine the biochemical effect of di-（2-ethylhexyl） phthalate （DEHP） on testes, liver, kidneys and pancreas on day 10 in the process of degeneration of the seminiferous epithelium. Methods： Diets containing 2% DEHP were given to male Crlj：CDI（ICR） mice for 10 days. The dose of DEHP was 0.90±0.52 mg/mouse/day. Their testes, livers, kidneys and pancreata were examined for detection of mono-（2-ethylhexyl） phthalate （MEHP）, nitrogen oxides （NOx） produced by peroxidation of nitric oxide （NO） with free radicals, and lipid peroxidation induced by the chain reaction of free radicals. Results： Histological observation and serum analysis showed the presence of severe sperrnatogenic disturbance, Leydig cell dysfunction, liver dysfunction and dehydration. Unexpectedly, the concentration of MEHP in the testes was extremely low compared with that in the liver. However, the concentration of the NOx in the testes was as high as the hepatic concentration. Furthermore, free radical-induced lipid peroxidation was histochemically detected in the testes but not in the liver. Conclusion： The results indicate that DEHP-induced aspermatogenesis is caused by the high sensitivity of the testicular tissues to MEHP rather than the specific accumulation or uptake of circulating MEHP into the testes.     

Biphasic effects of postnatal exposure to diethylhexylphthalate on the timing of puberty in male rats

Phthalate esters such as di(2-ethylhexyl)phthalate (DEHP), which are commonly found in cosmetics and in flexible plastics distributed by the food, construction, and medical products industries, have been classified as anti-androgens. High-dose DEHP exposure in utero is associated with decreased androgen levels. However, when administered after birth, low doses of DEHP (eg, 10 mg/kg body weight) may stimulate androgen production. In the present study, the potential of phthalate exposure to advance or delay the timing of puberty was assessed. Male Long-Evans rat pups were chronically subjected to low or high doses of DEHP, with the androgen-driven process of preputial separation serving as an index of pubertal timing. Rats were treated with 0, 10, 500, or 750 mg/kg body weight DEHP for 28 days starting at day 21 postpartum. The average age at which the animals completed preputial separation was measured in each group. The age of preputial separation was 41.5 +/- 0.1 days postpartum in controls (vehicle). The 10 mg/kg DEHP dose advanced pubertal onset significantly to 39.7 +/- 0.1 days postpartum, whereas the 750 mg/kg DEHP dose delayed pubertal onset to 46.3 +/- 0.1 days postpartum. The 10 mg/kg DEHP dose also significantly increased serum testosterone (T) levels (3.13 +/- 0.37 ng/mL) and seminal vesicle weights (0.33 +/- 0.02 g) compared with control serum T (1.98 +/- 0.20 ng/mL) and seminal vesicle weight (0.26 +/- 0.02 g), while the 750 mg/kg dose decreased serum T (1.18 +/- 0.18 ng/mL) as well as testes and body weights. Direct action of the DEHP metabolite, monoethylhexylphthalate (MEHP), on Leydig cell steroidogenic capacity was investigated in vitro. MEHP treatment at a low concentration (100 microM) increased luteinizing hormone-stimulated T production, whereas 10 mM concentrations were inhibitory. In conclusion, data from the present study indicate that DEHP has a biphasic effect on Leydig cell function, with low-dose exposure advancing the onset of puberty. High doses of DEHP, which are anti-androgenic, may also be outside the range of real environmental exposure levels.     

Dose-dependent effect of phthalate ester on testicular descent in pre-and post natal rats

Mono-n-butyl phthalate (MBP) was administered to pregnant rats from the 15th to the 17th gestational day to investigate the dose-dependent effect of phthalate ester on testicular descent in both pre- and postnatal rats. Thirty pregnant rats (280–330 g) were separated into five groups and administered 1.0 g/kg/day MBP in group I, 0.5 g/kg/day in group II, 0.25 g/kg/day in group III, 0.125 g/kg/day in group IV from the day 15 to 17 of gestation. The rats in group V were only administered solvent and acted as controls. The position of the testis was evaluated in both pre- and postnatal rats. This was significantly higher in 20-day old fetuses in groups I and II than in groups III, IV or V. After birth, the incidence of undescended testis was also higher in groups I and II compared with those of groups III, IV or V. The undescended testes were located in the abdominal cavity in groups I and II, whereas they were located at the inguinal region in group III. The lowest dose that induced an adverse effect on testicular descent was 0.25 g/kg/day. In conclusion, maternal MBP inhibited testicular descent in prenatal rats and thus dose-dependently induced undescended testes postnatally. High-doses of MBP are thus considered to inhibit the transabdominal descent of the testis, probably due to its estrogenic activity, whereas low-doses of MBP may act as an anti-androgen and thereby inhibit inguinoscrotal testicular descent in postnatal rats.     

睾丸生精小管干细胞移植受体模型建立与移植技术改进

目的:探讨建立稳定的、适合干细胞睾丸生精小管移植的受体小鼠模型和移植技术改进。方法:将雄性ICR小鼠60只随机分为A、B、C、D4组,每组15只。A、B、C组注射白消安的剂量分别为15、30、40mg/kg体重,D组注射50%二甲亚砜作为对照。注射后常规饲养,观察小鼠死亡情况。于注射后4、8、12周称量各组小鼠的睾丸重量,制作睾丸石蜡切片,观察生精小管的中空率和生精上皮结构变化。自主设计干细胞移植装置,改进干细胞移植技术。该装置通过三通连接装置将口含端、注射器端及穿刺端连接在一起,口含端负责试探性的注射,注射器端负责抽吸细胞悬液和注射。结果:注射后只有C组出现1只小鼠死亡。4周时A、B、C组睾丸重量的变化,与作为对照的D组相比有显著性差异(P<0.05);8周时A组与D组无差异(P>0.05),而B、C组与D组差异仍有显著性(P<0.05);12周时各组与D组均无显著性差异(P>0.05)。4、8周时A组的生精小管中空率<50%,B、C组中空率都在50%以上,而D组无明显改变;12周时A、B、C组无显著性差异(P>0.05),恢复近正常状态。自主设计的三通式注射装置注射成功率高,可达90%以上;细胞浪费少,注射双侧睾丸所需细胞悬液量<50μl;所需时间短,注射一侧睾丸<10min。结论:雄性ICR小鼠腹腔内单次注射30mg/kg体重白消安,无小鼠死亡,且4周后生精小管的中空率高(均>50%),适合作为干细胞移植的模型。改进后的移植装置和方法,提高了移植的效率和成功率。为探讨干细胞向雄性配子发育研究提供了简单易学、适于推广的新技术。     

L-肉碱在奥硝唑所致大鼠睾丸和附睾损伤中的保护作用

目的:探讨L-肉碱(LC)在奥硝唑(ORN)所致大鼠附睾和睾丸损伤中的的保护作用。方法:40只雄性SD大鼠(200～230g)随机均分为5组:①A组:给予0.5%的羧甲基纤维素钠(溶剂)灌胃;②B组:每天给予400mg/kgORN灌胃;③C组:每天给予800mg/kgORN灌胃;④D组:每天给予[ORN(400mg/kg)+LC(100mg/kg)]灌胃;⑤E组:每天给予[ORN(800mg/kg)+LC(100mg/kg)]灌胃。上述各组均连续灌胃20d,末次给药24h后,所有大鼠麻醉后处死,分别取睾丸、附睾,进行称重和HE染色,计算睾丸、附睾系数并观察睾丸和附睾病理组织学改变。结果:①与A组相比,B组睾丸、附睾系数明显降低(P<0.05);而C组睾丸、附睾系数为极显著性降低(P<0.01);D组与A组相比无差异,E组与A组相比有极显著性差异(P<0.01);②HE染色显示,与A组相比,B组睾丸生精小管内各级生精细胞排列基本整齐,部分生精小管管腔内有脱落的生精细胞,附睾管腔中精子数目下降,有时可见散在的生精细胞;C组大鼠睾丸生精小管管腔内均可见坏死脱落的生精细胞,附睾管腔中精子数目明显减少,且有较多的非精子细胞成分。D组睾丸生精小管无明显改变,附睾管腔中精子数目也未见明显下降;E组睾丸生精小管管腔内精子数目减少,可见坏死脱落的生精细胞,附睾腔中精子数目明显减少,并伴有较多的非精子细胞成分。结论:奥硝唑(ORN)可导致雄性大鼠附睾和睾丸病理组织学改变,LC对ORN引起大鼠附睾和睾丸损伤具有一定的保护作用。     

Therapeutic effect of thymoquinone against lead‐induced testicular histological damage in male Wistar rats

Lead (Pb) is a nonthreshold multi‐targeted toxicant that causes alterations in different organs of the body, especially the gonads. This study was aimed to investigate the possible protective effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb‐induced testicular histological damage. Adult male rats were randomised into four groups as follows: control group received no treatment, Pb group was exposed to 2000 ppm of Pb acetate in drinking water, Pb‐TQ group was cotreated with Pb plus TQ (5 mg/kg/day, per os) and TQ group receiving only TQ. All treatments were applied for five weeks. Results showed that Pb exposure produced morphological changes in the testis, especially degeneration of germinal epithelium, sloughing of germ cells into the lumen of seminiferous tubules and reduction in the number of luminal spermatozoa. Interestingly, coadministration of TQ to the metal‐treated animals prevented the testicular adverse effects. In conclusion, our data indicate for the first time a remarkable protective effect of TQ against Pb‐induced testicular histopathological lesions in rat. On this basis, TQ deserves more consideration and further examination as a potential therapeutic option.     

Acute and long-term effects of a single dose of the fungicide carbendazim (methyl 2-benzimidazole carbamate) on the male reproductive system in the rat.

The effects of carbendazim (methyl 2-benzimidazole carbamate) on the testis, efferent ductules, and sperm were determined in the adult rat after a single oral dose. Two experimental trials were performed: a time response between 2 hours and 32 days after exposure using 0 and 400 mg/kg, and a dose response at 2 and 70 days after exposure using 0 to 800 mg/kg doses. In experiment 1, effects were seen throughout the 32-day period, beginning 8 hours after exposure; the effects included first an increase in testis weight, then decreases in testicular spermatid numbers and in the percentage of morphologically normal cauda sperm. In experiment 2, significant testicular and efferent ductal alterations occurred in animals treated with doses of 100 mg/kg or greater. A dose-dependent increase in testicular weight 2 days after treatment was accompanied by increases in seminiferous tubular diameter and excessive loss of immature germ cells in a stage-dependent manner. There was also a dose-dependent increased incidence of occlusions in the efferent ductules. The occluded ductules were characterized by severe inflammation and exhibited disorganization of the epithelium. At 70 days, there were dose-dependent decreases in mean testis weight and mean seminiferous tubular diameter; however, only minimal long-term effects were seen at 50 mg/kg. In testes exhibiting seminiferous tubular atrophy of greater than 25% (100 mg/kg or greater doses), all of the testes were associated with efferent ductules containing occlusions. Caput sperm numbers were significantly reduced in these testes. Occlusions, abnormal ductules, fibrosis, spermatic granulomas, and mineralization were observed in the ductuli efferents. Long-term effects of carbendazim on the testis were induced primarily by ductal occlusions. Results show that carbendazim produces more severe short- and long-term effects on the male reproductive system than the fungicide benomyl.