畜牧兽医学报  2020, Vol. 51 Issue (6): 1455-1465. DOI: 10.11843/j.issn.0366-6964.2020.029    PDF    
性激素受体在子午岭黑山羊隐睾及正常睾丸中的分布比较
王乾梅, 袁莉刚, 李承晔, 杨洪早, 陈少宇     
甘肃农业大学动物医学院, 兰州 730070
摘要:旨在研究性激素受体[雄激素受体(androgen receptor,AR)、雌激素受体(estrogen receptor,ER)]在子午岭黑山羊正常睾丸与隐睾组织中的分布与隐睾症的关系,应用免疫组织化学及免疫荧光技术方法结合形态计量学统计软件,比较了正常睾丸与隐睾的组织化学特点。特殊染色结果显示:与正常组相比,隐睾组间质组织疏松,管腔面积明显减小,糖原含量明显减少,胶原纤维及网状纤维含量增多。免疫组化及免疫荧光结果显示:1)AR在正常睾丸组Leydig细胞呈高密度强阳性表达,在各级生精细胞呈中等强度阳性表达,隐睾组中Leydig细胞及各级生精细胞表达明显减弱,且在精原细胞偶见表达;2)ER在正常睾丸Leydig细胞呈高密度强阳性表达,管周肌样细胞呈中等强度阳性表达,Sertoli细胞偶见表达,各级生精细胞无表达;3)ER在隐睾Leydig细胞、初级精母细胞、精原细胞和Sertoli细胞中均呈中等强度阳性表达;4)统计结果显示,隐睾组AR的平均光密度较正常组显著降低(P < 0.05),而ER的平均光密度则显著高于正常组(P < 0.01),且隐睾组AR与ER表达量比值基本接近1:1。子午岭黑山羊隐睾组织胶原纤维和网状纤维分布较正常睾丸多,生精小管基膜主要成分以中性糖蛋白为主,酸性糖蛋白含量明显降低影响精子的正常形成;隐睾组织精原细胞及Sertoli细胞ER与AR表达失常尤为明显,可为哺乳动物隐睾的相关研究提供一定参考。
关键词子午岭黑山羊    雄激素受体    雌激素受体    睾丸    隐睾    
Distribution of Sex Hormone Receptors in Cryptorchidism and Normal Testes of Ziwuling Black Goat
WANG Qianmei, YUAN Ligang, LI Chengye, YANG Hongzao, CHEN Shaoyu     
College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
Abstract: To study the relationship between the distribution of sex hormone receptors (AR and ER) in normal and cryptorchid testis and cryptorchidism of the Ziwuling black goat, the histochemical characteristics of normal testis and cryptorchidism were compared by immunohistochemistry, immunofluorescence and morphometric statistical software. The results of special staining showed that compared with the normal group, the interstitial tissue of cryptorchidism group was loose, the lumen area was significantly reduced, the content of glycogen was significantly decreased, and the contents of collagen and reticular fibers were increased. The results of immunohistochemistry and immunofluorescence showed that:1) AR was strongly expressed in Leydig cells of the normal testis and moderately positive in all levels of spermatogenic cells, while the expression of Leydig cells and Spermatogenic cells in cryptorchidism group was significantly decreased and occasionally expressed in Spermatogonia. 2) ER was strongly expressed in the normal testicular Leydig cells, moderately positive in Peritubular myoid cells, occasionally expressed in Sertoli cells and not expressed in Spermatogenic cells. 3) ER was moderately positive in cryptorchidism Leydig cells, primary Spermatocytes, Spermatogonia and Sertoli cells. 4) The average optical density of AR in cryptorchidism group was significantly lower than that in the normal group, while the average optical density of ER in cryptorchidism group was significantly higher than that in the normal group. The ratio of AR to ER expression in cryptorchidism group was close to 1:1. The distribution of collagen and reticular fibers in cryptorchidism of Ziwuling black goat is more than that of the normal testis, and the main component of seminiferous tubule basement membrane is the neutral glycoprotein. The decrease of the content of acid glycoprotein may affect the normal formation of spermatozoa. The expression of ER and AR is abnormal during cryptorchidism, especially the expression of spermatogonia and Sertoli cells is opposite to that of AR, which can provide some reference for the related research of cryptorchidism in mammals.
Key words: Ziwuling black goat    androgen receptor    estrogen receptor    testis    cryptorchidism    

雄激素(androgen)和雌激素(estrogen)是哺乳动物体内重要的性激素,其主要在生殖器官的生殖调控、生长发育及维持第二性征等方面发挥作用。动物体内雌激素或雄激素都必须与靶细胞上的特异性蛋白——雌激素受体(estrogen receptor,ER)和雄激素受体(androgen receptor,AR)特异性结合才能发挥其生理功能[1]。雄激素是由睾丸间质细胞(Leydig cell)产生,其受体在细胞质中通过与其结合激活而发挥作用,活化后的AR释放热休克蛋白并导入细胞核,发挥转录因子的作用,AR的靶基因涉及性腺发育等相关生物学过程[2-3]。AR在精子发生中的生物学机制及其在生殖细胞中的表达是研究的热点[4]。外源性雌激素效应与雄性泌尿系统发育异常及内分泌紊乱密切相关,研究证明男性生殖系统异常与胎儿期母体及胎儿的雌激素暴露程度相关,外源性雌激素效应在雄性动物体内主要是通过ER起作用[5]。ER在雄性生殖过程中起着至关重要的作用,在大多数睾丸细胞中均有表达[6-8]。雄性小鼠ER缺失与精子发生异常和不育有关[9]

在激素调节下,胚胎发生后期睾丸从腹腔下降到阴囊。研究显示,雄激素与胚胎期睾丸引带发育密切相关,而外源性雌激素通过受体作用干扰下丘脑-垂体-睾丸轴,从而减少雄激素分泌,引起睾丸引带功能障碍,导致隐睾[10]。隐睾症相关研究主要集中于人类及啮齿类动物,针对牛羊等家畜的报道不多。最新调查研究显示,新生儿隐睾症发病率为3.4%~5.8%,山羊中隐睾症发病率为0.5%,在长期近亲交配的羊群中,其发病率可高达10%以上[11-12]。免疫组化研究结果显示,隐睾组睾丸周围组织鞘膜及睾丸引带中AR表达率低于正常组,鞘突中ER的阳性表达率则明显高于正常组,除此之外,雄激素阻断可引起小鼠隐睾症[13]。Carreau等[14]研究发现,敲除ERα基因的小鼠会出现睾丸精子形态异常、数量及活性降低,甚至生育能力下降等症状。国内对动物隐睾研究表明,小型巴马克隆猪隐睾睾酮激素分泌量减少、AR基因的异常表达可能是引起克隆猪发生隐睾的原因之一[15]。子午岭黑山羊是我国西北地区山羊的优势品种之一,地方性品种自交配引发隐睾的概率较高。本研究通过组织化学染色及免疫组织化学法和免疫荧光技术,比较分析子午岭黑山羊正常睾丸和隐睾AR、ER以及糖原等组织成分的分布变化,探究其与隐睾症的关系,为子午岭黑山羊睾丸病理和生殖生理研究提供形态学参考资料。

1 材料与方法 1.1 试验材料

1.1.1 实验动物   样品采自甘肃省庆阳市环县牧区4月龄子午岭黑山羊正常睾丸及隐睾,隐睾位于腹股沟管内,外科手术取出睾丸,共8例,其中4例为隐睾, 固定于4%福尔马林固定液中备用。

1.1.2 主要药品试剂及仪器   Masson三色染色试剂、Gomori银氨法网状纤维染色液、标准阿利新蓝染色液(pH=2.5);雌激素受体相关蛋白α抗体(bs-6998R)、雄激素受体抗体(bs-0118R);荧光素Alexa Fluor 488标记链霉亲和素(bs-0437P-AF488)、荧光素Alexa Fluor 555标记链霉亲和素(bs-0437P-AF555)、DAPI染色液(D-9106);免疫组化染色试剂盒(SP-0023),以上材料均购自北京博奥森生物技术有限公司。DAB显色试剂盒(ZLI-9018)购自北京中杉金桥生物技术有限公司。

Epon812包埋机,NIKON ECLIPSE 80i显微摄像系统,LKB8800型超薄切片机,正倒置一体荧光显微镜(RVL100-G, ECHO, USA),激光扫描共聚焦显微镜(LSM800, Carl Zeiss, Germany)。

1.2 试验方法

1.2.1 样品制备   新鲜组织样品切取1 cm×1 cm×0.6 cm大小,经4%多聚甲醛溶液固定一周备用;常规梯度酒精脱水,石蜡包埋,超薄切片机连续切片(片厚4 μm),相邻切片分为10套,分别用于ER、AR免疫组织化学染色及免疫荧光染色;苏木素-伊红(HE)常规染色、Masson胶原纤维染色、Gomori银氨法染色、阿利新蓝(Alcian,AB)染色、糖原PAS过碘酸雪夫染色、过碘酸雪夫AB-PAS染色。

1.2.2 免疫组织化学法   免疫组织化学法进行染色:1)石蜡切片常规脱蜡;2)PBS振洗3次,每次5 min,高压法暴露抗原,冷却至室温,PBS振洗;3)滴加30 g·L-1 H2O2阻断过氧化物酶活性,37 ℃孵育15 min,随后PBS振洗3次,每次5 min;4)滴加山羊血清白蛋白,37 ℃孵育15 min后,倾去血清;5)分别滴加雌激素受体相关蛋白α抗体(稀释度1:400)和雄激素受体抗体(稀释度1:400),阴性对照组用PBS代替抗体,37 ℃孵育4 h后,PBS振洗;6)滴加生物素标记山羊抗兔IgG二抗工作液,孵育15 min;PBS振洗;7)依次滴加50 μL辣根酶标记链霉卵白素工作液,37 ℃孵育,PBS振洗;8)滴加新鲜配制的DAB显色液置于暗盒显色,常规脱水、透明、封片。

1.2.3 免疫荧光法   石蜡切片常规脱蜡,高压暴露抗原,滴加H2O2阻断,山羊血清白蛋白进行封闭,操作步骤均与免疫组织化学相同,将生物素标记山羊抗兔IgG二抗替换为荧光素Alexa Fluor 488标记链霉亲和素(稀释度1:800)孵育2 h,采用正倒置一体荧光显微镜观察拍照。

1.2.4 免疫荧光双染   石蜡切片常规脱蜡,高压暴露抗原,滴加H2O2阻断,山羊血清白蛋白进行封闭,操作步骤均与免疫组织化学相同,将生物素标记山羊抗兔IgG二抗替换为荧光素Alexa Fluor 555标记链霉亲和素(稀释度1:800)孵育90 min,PBS振洗3次,每次5 min;DAPI染色液孵育10 min后,PBS振洗,激光扫描共聚焦显微镜观察拍照。

1.3 数据统计

切片在NIKON ECLIPSE 80i显微摄像系统进行照相。每组随机选取5张切片,分别拍摄6个不重复视野(正常组400×, 隐睾组1 000×)。用Image Pro Plus 6.0软件统计每个视野下横切面圆管形生精小管内Sertoli细胞数,生精小管管径、横截面积及周围间质组织面积,进而计算间质面积/管腔面积,同时计算免疫组化平均光密度值。

免疫荧光染色在正倒置一体荧光显微镜观察拍照。每组随机选取5张切片,每张切片拍摄6个不重复视野(正常组200×,隐睾组400×)。采用半定量的形式对染色结果的分布密度进行描述,SPSS 15.0统计学软件进行分析;P<0.05为差异有显著性意义。

2 结果 2.1 子午岭黑山羊正常睾丸及隐睾组织化学特征比较

光镜下,子午岭黑山羊正常睾丸间质结缔组织明显,生精上皮由3~5层生精细胞及Sertoli细胞构成,生精小管排列紧密,管周肌样细胞分布于生精小管固有膜外周,核呈长索形(图 1A);生精小管固有膜胶原纤维稀疏,Leydig细胞散在分布于胶原纤维之间(图 1B);生精小管固有膜及间质血管外周基膜网状纤维较为丰富(图 1C);AB蓝色阳性反应生精小管周围分布较多,即酸性糖原含量高(图 1D);PAS染色阳性反应强,蓝紫色条带分布明显,即中性糖原含量较多(图 1E);AB-PAS染色,紫红色阳性反应条带明显,即混合性糖原含量高(图 1F)。

A~F.正常睾丸组织染色,400×,标尺示50 μm;G~L.隐睾组织染色,1 000×,标尺示20 μm。A. HE染色;B.改良Masson胶原纤维染色,胶原纤维呈蓝色;C. Gomori银氨法网状纤维染色,黑色条状为网状纤维;D. AB染色,酸性糖原呈蓝色;E. PAS染色,中性糖原呈蓝紫色;F. AB-PAS染色,混合性糖蛋白呈紫红色;G.隐睾组织HE染色;H.隐睾组织改良Masson胶原纤维染色;I.隐睾组织改良Masson胶原纤维染色;J.隐睾组织AB染色;K.隐睾组织PAS染色;L.隐睾组织AB-PAS染色;ST.生精小管;Ley.Leydig细胞;CF.胶原纤维;RF.网状纤维;AG.酸性糖原;NG.中性糖原;MG.混合性糖原 A-F. Normal testicular group staining, 400×, Bar=50 μm; G-L. Cryptorchidism tissue staining, 1 000×, Bar=20 μm. A. HE staining; B. Modified Masson collagen staining showed that collagen fibers were blue; C. Gomori silver ammonia reticular fiber staining, black strip reticular fiber; D. AB staining, Acid glycogen were blue; E. PAS staining, Neutral glycogen were blue-purple; F. AB-PAS staining, Mixed glycogen were purplish red; G. HE staining, H. Modified Masson collagen fiber staining; I. Modified Masson collagen fiber staining; J. AB staining; K. PAS staining; L. AB-PAS staining; ST. Seminiferous tubule; Ley. Leydig cells; CF. Collagen fibers; RF. Reticular fiber; AG. Acid glycogen; NG. Neutral glycogen; MG. Mixed glycogen 图 1 子午岭黑山羊正常睾丸及隐睾组织化学特征比较 Fig. 1 Comparison of histochemical characteristics of normal testes and cryptorchidism in Ziwuling black goat

与正常睾丸比,隐睾间质组织中毛细淋巴管及血管散在分布于结缔组织之间,生精上皮由2~3层细胞组成,生精小管皱缩,以Sertoli细胞数量居多,Leydig细胞核散分布于结缔组织之间(图 1G);间质生精小管外周胶原纤维分布增加(图 1H);生精小管固有膜及间质组织中网状纤维分布明显(图 1I);PAS及AB染色显示间质组织阳性反应明显减弱(图 1J1K);AB-PAS染色,蓝色酸性糖蛋白在间质组织及生精小管固有膜着色较淡,红色中性糖蛋白反应明显(图 1L)。

统计结果显示,与正常组相比,隐睾生精小管平均直径减小(P < 0.01,表 1),生精小管内Sertoli细胞数量增加(P < 0.05),间质组织面积/管腔面积显著增加(P < 0.01)。

表 1 子午岭黑山羊正常睾丸与隐睾生精小管特征指数比较(x±s) Table 1 Comparison of characteristic index of spermatogenic tubules between normal testis and cryptorchidism in Ziwuling black goat(x±s)
2.2 ER、AR在子午岭黑山羊正常睾丸及隐睾中的分布定位

AR、ER在正常睾丸及隐睾组织中免疫组织化学法及免疫荧光技术检测结果表明(图 23表 2),正常睾丸组织中AR在Leydig细胞、管周肌样细胞中均呈高密度强阳性表达;在Sertoli细胞呈强阳性表达,各级生精细胞均呈中等强度阳性表达。AR在隐睾组织Leydig细胞、管周肌样细胞、Sertoli细胞及各级生精细胞中表达均较正常组织减弱。ER在正常睾丸Leydig细胞呈高密度强阳性表达,在部分管周肌样细胞呈中等强度阳性表达,Sertoli细胞偶见表达,在各级生精细胞则无表达。隐睾中,ER主要在Leydig细胞、初级精母细胞、精原细胞及Sertoli细胞均呈中等强度阳性表达。

上方6张为免疫组织化学染色法(标尺示50 μm);下方6张为免疫荧光染色法(标尺示100 μm);ST.生精小管; Ley. Leydig细胞; Sg.精原细胞; SC.Sertoli细胞 The upper 6 pictures were immunohistochemical staining (Bar=50 μm); The lower 6 pictures were immunofluorescence staining (Bar= 100 μm); ST. Seminiferous tubule; Ley. Leydig cells; Sg. Spermatogonia; SC. Sertoli cells 图 2 AR、ER在子午岭黑山羊正常睾丸及隐睾组织分布定位比较 Fig. 2 Comparison of distribution of AR and ER in normal testes and cryptorchidism of Ziwuling black goat
红色组织显示AF555的荧光着色;黑色区域表示背景;蓝色组织表示DAPI标记的核荧光着色;ST.生精小管;Ley. Leydig细胞;PC.管周肌样细胞;SC. Sertoli细胞 Red tissue indicates fluorescence coloration of AF-555 secondary antibodies; Black area indicates background; Blue tissue indicates fluorescence coloration of nuclear labeling by DAPI; ST. Seminiferous tubule; Ley. Leydig cells; PC. Periductal myoid cells; SC. Sertoli cells 图 3 正常和隐睾睾丸中AR、ER免疫荧光双重染色标记(标尺=50 μm) Fig. 3 AR and ER immunofluorescence staining in normal and cryptorchid testis(Bar=50 μm)
表 2 AR、ER在子午岭黑山羊睾丸正常组和隐睾组中不同部位的分布密度 Table 2 Distribution densities of AR and ER in different parts of normal testis and cryptorchidism in Ziwuling black goats

平均光密度值统计显示(图 4),隐睾中AR的平均光密度较正常睾丸显著降低(P < 0.05),而ER的平均光密度则显著高于正常睾丸(P < 0.01);且隐睾中AR与ER表达量比值基本接近1:1。对不同位置光密度表达变化结果统计显示(图 5),与正常睾丸相比,隐睾精原细胞中AR表达明显降低,ER在隐睾中精原细胞及Sertoli细胞的表达量则显著升高。

**.P < 0.01,表示组间差异极显著;*.P < 0.05,表示组间差异显著 **.P < 0.01, indicating that the difference between the groups is very significant; *.P < 0.05, indicating that the difference between the groups is significant 图 4 AR、ER在子午岭黑山羊睾丸正常组和隐睾组中平均光密度值统计结果 Fig. 4 Statistical results of average optical density of AR and ER in normal testis and cryptorchidism of Ziwuling black goat
a. AR;b. ER;Ley.间质细胞;PS.初级精母细胞;PC.管周肌样细胞;Sg.精原细胞;SC.支持细胞 a. AR; b. ER; Ley. Leydig cells; PS. Primary spermatocytes; PC. Periductal myoid cells; Sg. Spermatogonia; SC. Sertoli cells 图 5 AR、ER在子午岭黑山羊睾丸正常组和隐睾组中不同细胞表达变化 Fig. 5 The expression of AR, ER in different cells of normal testicular group and cryptorchidism group of Ziwuling black goat
3 讨论 3.1 子午岭黑山羊正常睾丸和隐睾间质组织成分的比较分析

哺乳动物睾丸间质结缔组织是血管、淋巴管以及Leydig细胞等存在的组织支架,其相应的形态学及生理学变化会影响局部组织的营养代谢,大鼠生精小管管周的网状纤维可为生殖上皮结构提供支持,实验性精索静脉曲张缺氧通常伴随着睾丸一定程度的纤维化[16];研究显示,牛睾丸间质结缔组织的变化可能会影响睾丸局部代谢[17],其与生精上皮的发育密切相关,结缔组织增加会影响精子质量[18];高原地区反刍动物睾丸的研究表明,牦牛隐睾较正常睾丸生精小管管径明显减小,间质/管腔面积比显著增大,间质胶原纤维异常增生[19]。本研究中与正常睾丸组织结构相比,隐睾组生精小管管径减小且间质/管腔面积比显著增大。Suskind等[20]研究发现,睾丸纤维化程度与其功能呈负相关。胶原纤维是细胞外基质的组织者,参与构成复杂的网络系统,并将多种成分有机的连接起来,其含量与生理功能密切相关,正常组织中胶原纤维的生成和降解处于动态平衡[21],关于睾丸热应激研究显示,对大鼠睾丸进行局部加热处理后,胶原纤维大量增生,与此同时,整个睾丸出现明显纤维化[22-23]。与此一致,本试验隐睾组为腹股沟管隐睾,发育过程中温度亦高于正常组,与正常组相比,隐睾组间质组织胶原纤维及网状纤维含量增多,隐睾生精小管发育不全且局部有纤维化趋势。

生精上皮发育过程中糖类物质是精子发生所必须的营养,可通过血管及生精小管固有膜提供给上皮。PAS、AB及AB-PAS阳性反应的糖原、硫酸基糖蛋白以及酸性、中性糖蛋白很典型的存在于睾丸结缔组织、黏液以及基膜中。研究表明,短吻鳄睾丸AB-PAS阳性主要位于睾丸间质结缔组织、生精小管基膜以及Leydig细胞,PAS阳性反应则分布于生精小管基膜、睾丸间质结缔组织以及leydig细胞[24],除此之外,大鼠睾丸PAS阳性反应随生精细胞的成熟而增强,即糖原类物质与生精细胞的增殖分化密切相关[25-27],与此研究相一致,本试验中隐睾组PAS阳性反应较正常组显著减弱,提示隐睾组织生精功能下降与糖原物质含量降低有关。AB染色阳性表达物质——硫酸基糖蛋白,主要由Sertoli细胞分泌且在睾丸发育的不同阶段具有不同的生物学作用,性成熟前,其主要以影响Sertoli细胞的分化成熟为主,性成熟之后则主要参与精子尾部细胞骨架的形成[28],在精子的变形期具有一定调节作用;本试验隐睾组AB及AB-PAS染色阳性表达较正常组均明显降低,提示隐睾组织中酸性糖蛋白含量减少,且生精小管基膜主要成分以中性糖蛋白为主,酸性糖蛋白含量明显降低可能会影响精子的正常形成。

3.2 AR、ER在子午岭黑山羊正常睾丸和隐睾组织中的分布比较

睾丸中有多种细胞表达AR,主要有Leydig细胞、Sertoli细胞、管周肌样细胞及各级生精细胞。研究表明,大鼠睾丸Leydig细胞出生后的成熟过程分为间充质样前体细胞、未成熟Leydig细胞和成熟Leydig细胞,AR的表达强度在幼龄组大鼠睾丸Leydig细胞呈中等强度表达,成年组Leydig细胞呈高密度强阳性表达,在老龄组睾丸Leydig细胞中则阳性表达较弱[29-30],本试验中,正常组AR在Leydig细胞呈高密度强阳性表达,隐睾组表达则明显降低,结果显示,Leydig细胞中AR的表达强度与睾丸生精能力呈正相关。研究发现,雄激素在管周肌样细胞均呈强阳性表达,其表达强度与年龄段无相关性[31],Welsh等[32]研究发现,构建管周肌样细胞AR基因特异性敲除小鼠,结果显示,睾丸质量减小,微血管受损,生精小管面积减小,但小鼠并未出现不育情况。本试验中,与正常组相比,隐睾组管周肌样细胞AR显著降低,Sertoli细胞AR表达减弱,提示隐睾Sertoli细胞AR表达减少与生精障碍关系密切。最新研究表明,AR的基因多态性与隐睾症的发生相关[33],AR在小鼠睾丸发育过程表达变化显示,成年期小鼠睾丸生精细胞内无AR表达,与此相反,在14 d至出生后56 d的小鼠睾丸组织中均可观察到AR在精原细胞中呈中等强度阳性表达[34-35]。牦牛性成熟前期,AR在Sertoli细胞和精原细胞呈强阳性表达,初级精母细胞呈高密度强阳性表达,且间质细胞阳性表达随年龄呈增长趋势[36]。本研究中正常组中AR在各级生精细胞呈强阳性表达,隐睾组中AR在精原细胞中偶见阳性表达,但初级精母细胞则无表达;提示隐睾时AR亦相应降低,且主要在精原细胞减数分裂阶段差异显著,其调控机制需进一步分析验证。

血-睾屏障(blood-testis barrier, BTB)为生精小管与毛细血管血液之间的屏障结构,阻止某些物质进入生精上皮,同时形成有利于精子发生的微环境,以此防止抗原物质(如精子)逸出到生精小管外而发生自体免疫反应。最新研究表明,ER信号转导通路的激活可以干扰BTB导致精子发生功能障碍,Sertoli细胞是其主要作用靶点[37-39]。免疫组化结果显示,正常小鼠睾丸组织内Leydig细胞及20%的管周肌样细胞ER表达呈阳性,Sertoli细胞及生精细胞则无明显表达[40],与此研究一致,本试验中正常组ER在Sertoli细胞及精原细胞无表达,在Leydig细胞呈高密度强阳性表达,管周肌样细胞中呈中等强度阳性表达。研究表明,ER及热休克蛋白在内的信号转导障碍与精子发生阻滞导致的不育密切相关[41-42],敲除正常雄性小鼠睾丸组织ER基因,可导致不育[43-45]。本研究中,与正常组相比,隐睾组织ER在Leydig细胞、初级精母细胞显著降低,提示隐睾生精过程ER表达失常。Strauss等[46]研究表明,雄激素和雌激素在体内水平比率失衡比单纯的雄激素或雌激素浓度变化更易引起Leydig细胞功能异常,从而影响精子发生,但对于雄激素与雌激素导致Leydig细胞功能异常的具体比例目前尚无研究报道。本试验平均光密度分析结果显示,隐睾组织中AR表达量较正常睾丸显著降低,ER表达量则明显上升,隐睾中AR与ER表达量比值基本接近1:1,且ER在Sertoli细胞的表达与AR的表达趋势相反,提示隐睾中性腺激素受体分布失衡亦可为其特征性变化之一,可为后续研究提供一定参考。

4 结论

子午岭黑山羊隐睾组织胶原纤维和网状纤维分布较正常睾丸多,生精小管基膜主要成分以中性糖蛋白为主,酸性糖蛋白含量明显降低可能会影响精子的正常形成;隐睾生精过程ER与AR表达失常,且ER在隐睾Leydig细胞、初级精母细胞、管周肌样细胞差异显著,且与AR的变化趋势相反,可为哺乳动物隐睾症的相关研究提供一定参考。

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