bcl—2基因在小鼠睾丸及试验隐睾中表达的研究

目的 研究ｂｃｌ－２基因在正常小鼠睾丈中的定位表达及试验隐睾所导致的改变。方法 以Ｗｅｓｔｅｒｎ－ｂｌｏｔｔｉｎｇ印迹法从蛋白水平检测ｂｃｌ－２基因在正常小鼠睾及及试验隐睾中的表达、变化;地高辛标记ｂｃｌ－２基因ｃＤＮＡ探针,石蜡组织切片原位杂交技术,从ｍＲＮＡ水平检测ｂｃｌ－２基因在小鼠精上皮中的定位及试验隐睾所导致的改变。结果 ｂｃｌ－２蛋白在正常小鼠睾丸中有较丰富的表达,试验隐睾导致其表达明显降低;ｂｃｌ－２基因在生精细胞中有较高水平的ｍＲＮＡ转录,表达细胞主要为各级生精细胞,支持细胞和间质细胞未见表达,隐睾术后仍然保持较高水平的ｍＲＮＡ转录。结论 ｂｃｌ－２蛋白可能在生精细胞主动退化的调节中起着重要作用。     

实验性隐睾诱导小鼠生精细胞凋亡的研究

目的 研究手术隐睾所致成年小鼠生殖细胞凋亡及相关调节因子ｂｃｌ－２、ｂａｘ蛋白在曲细精管中的定位、变化。方法 以末端脱氧核糖核酸转移酶介导的ｄＵＴＰ缺口末端标记法（ＴＵＮＥＬ）检测凋亡的生殖细胞,生物素－抗生物素蛋白ＤＣＳ体系间接免疫荧光法检测Ｂｃｌ－２、Ｂａｘ蛋白在曲细精管中的定位、分布。结果 隐睾术后３ｄ,手术侧睾丸重量及细胞凋亡数量与对侧地无明显区别。而６￣１５ｄ,睾丸重量明显减轻,凋亡细胞     

N-硝基-L-精氨酸甲酯对大鼠隐睾生精细胞凋亡的影响

目的：研究N-硝基-L-精氨酸甲酯(L-NAME)对实验性大鼠隐睾生精细胞凋亡的影响及其作用机制。方法：手术建立大鼠单侧隐睾模型，术后分别注射L-NAME及生理盐水，7d后采用流式细胞术检测2组大鼠隐睾生精细胞凋亡，免疫组化法检测隐睾内Bcl-2和Bax基因表达变化。结果：实验组隐睾重量较对侧正常睾丸重量减轻的程度低于对照组，生精细胞凋亡百分比及Bax表达较对照组低，而Bcl-2表达较对照组高。结论：L-NAME可通过调控Bcl-2和Bax的表达抑制隐睾导致的生精细胞凋亡。     

肝癌中bcl-2和bax基因的表达及其关系

目的：为了探讨巨细胞凋亡基因在肝癌发生中的作用。方法：利用免疫组化ＡＢＣ法,检测了肝癌中细胞凋亡抑制基因ｂｃｌ－２,促细胞凋亡基因ｂａｘ的表达。结果：ｂｃｌ－２以及ｂａｘ的个体阳性率均比正常对照组有显著性提高;肝癌组中ｂｃｌ－２和ｂａｘ的表达呈正相关,但无显著性。结论：ｂｃｌ－２表达抑制细胞凋亡,导致肝癌发生;ｂａｘ表达促进细胞凋亡,使肿瘤维持在高殖状态 。     

ZNF185基因的克隆及在小鼠睾丸中的定位

目的:克隆ZNF185基因并检测ZNF185在小鼠睾丸中的定位。方法:从小鼠睾丸中提取RNA,经RT-PCR,再对目的片段进行克隆和鉴定;提取小鼠肝、睾丸与卵巢组织的蛋白质,进行Western blot分析;制备小鼠睾丸冰冻切片,应用免疫荧光技术分析。结果:(1)ZNF185基因克隆完全正确。(2)Western blot显示,睾丸中的ZNF185含量最多。(3)免疫荧光显示,ZNF185定位于睾丸间质细胞和精子,在睾丸间质细胞表达较弱,而在圆形精子和成熟精子高表达。结论:成功克隆了ZNF185基因,并初步探明了ZNF185在小鼠睾丸中的定位。     

N-硝基-L-精氨酸甲酯对大鼠实验性隐睾生精细胞凋亡及Bax表达的影响

目的研究N-硝基-L-精氨酸甲酯(L-NAME)对大鼠实验性隐睾生精细胞凋亡及凋亡相关基因Bax表达的影响。方法手术建立大鼠单侧隐睾模型,实验分为隐睾组、隐睾 L-NAME组[术后腹腔注射溶于生理盐水的L-NAME 50 mg/(kg.d)]、隐睾 生理盐水组、假手术组,7 d后采用化学比色法检测睾丸组织NOS活性,流式细胞术(FCM)和原位缺口末端标记法(TUNEL)检测生精细胞凋亡,RT-PCR和免疫组织化学法检测Bax基因表达变化。结果隐睾组和隐睾 生理盐水组之间检测指标无明显差异;隐睾 L-NAME组隐睾凋亡细胞百分比和生精细胞凋亡指数均低于隐睾组及隐睾 生理盐水组,高于假手术组(P<0.05);Bax mRNA和蛋白表达水平隐睾组及隐睾 生理盐水组最高,假手术组次之,隐睾 L-NAME组最低。结论隐睾生精细胞Bax表达增加,L-NAME可通过下调Bax的表达抑制隐睾生精细胞凋亡。     

Seipin基因缺陷诱发小鼠肾损害

 目的:探讨seipin基因缺陷对小鼠肾脏结构和功能的影响及其可能的发病机制。方法:选取6月龄C57BL/6遗传背景的seipin基因敲除和野生型雄鼠,检测seipin基因在野生型小鼠各组织的表达;检测2组小鼠肾功能和病理改变,以及脂肪相关因子的表达。结果:Seipin基因在脂肪及睾丸中高表达,肾脏可检测到低水平seipin的表达,主要位于肾小球。与野生型小鼠相比,seipin敲除小鼠尿白蛋白及肌酐清除率增高;肾小球表面积增大、肾基质增多;血浆脂联素和瘦素水平下降,出现胰岛素抵抗。结论: Seipin基因缺陷可导致小鼠肾损害,可能与全身脂肪缺失引起的脂联素和瘦素水平下降相关。     

小鼠睾丸膜联蛋白A1的克隆、表达及定位

目的:克隆、表达小鼠睾丸膜联蛋白A1,并研究其在睾丸中的定位。方法:利用RT-PCR技术从小鼠睾丸组织中扩增膜联蛋白A1的cDNA序列,将该基因插入GST融合表达载体pGEX-5T。以亲和层析法纯化蛋白免疫家兔制备多抗,并做睾丸切片免疫组织化学检测。结果:重组质粒测序结果表明,插入片段与小鼠膜联蛋白A1的序列完全一致。K802重组菌高效表达出相对分子质量为63 000的融合蛋白,表达量占菌体总蛋白的30%。多抗效价达1∶102 400,可特异识别重组蛋白。免疫组织化学显示膜联蛋白A1主要分布于精原细胞核、精子细胞顶体帽及精子胞质残余体内。结论:成功克隆、表达了小鼠膜联蛋白A1基因;膜联蛋白A1在睾丸生精细胞中的不同分布预示其可能与生精过程有关。     

锌转运蛋白9在实验性脑疟小鼠脑内的表达改变

目的 探讨锌离子转运蛋白9在实验性脑疟小鼠大脑皮层和海马中的表达改变。方法 6周龄C57BL/6小鼠随机分为2组,对照组给予正常饮食,感染组（PbA组）经腹腔注射1×10 6个伯氏疟原虫（P.bergheiANKA）寄生的红细胞,采用吉姆萨染色检测红细胞感染率,并监测小鼠生存率;采用Western blot和免疫组织化学染色检测ZnT9在大脑皮层和海马中的表达改变;激光共聚焦扫描显微镜检测ZnT9在小鼠大脑中的共定位表达。结果 PbA感染组在感染后5-7天逐渐出现脑疟症状,外周血红细胞内有大量感染的疟原虫存在。ZnT9主要定位于神经元中,ZnT9在实验性脑疟小鼠大脑皮层和海马中表达降低。结论 ZnT9在实验性脑疟小鼠神经元细胞中表达降低,可能参与调控锌离子在神经元内稳态的维持。     

Cryptorchidism-induced CFTR down-regulation results in disruption of testicular tight junctions through up-regulation of NF-κB/COX-2/PGE2

STUDY QUESTION Does elevated temperature-induced cystic fibrosis transmembrane conductance regulator (CFTR) down-regulation in Sertoli cells in cryptorchid testis disrupt testicular tight junctions (TJs) through the nuclear factor kappa B (NF-κB)/cyclooxygenase-2 (COX-2)/prostaglandin E(2) (PGE(2)) pathway? SUMMARY ANSWER Our results suggest that CFTR may be involved in regulating testicular TJs and the blood-testis barrier (BTB) through its negative regulation of the NF-κB/COX-2/PGE(2) pathway in Sertoli cells, a defect of which may result in the spermatogenesis defect in cryptorchidism. WHAT IS KNOWN ALREADY Cryptorchidism, or undescended testes, is known to result in defective spermatogenesis. Although an elevated testicular temperature is regarded as an important factor affecting spermatogenesis in cryptorchidism, the exact mechanism remains elusive. It is known that the expression of functional CFTR is temperature sensitive. Our previous study has demonstrated that CFTR negatively regulates NF-κB/COX-2/PGE(2) in bronchial epithelial cells. Disruption of TJs by COX-2/PGE(2) has been found in tumour cells. STUDY DESIGN AND METHODS Expression of CFTR, NF-κB, COX-2 and TJ proteins was examined in the testes of a surgical-induced cryptorchidism mouse model and a testicular hyperthermia mouse model, as well as in control or CFTR-inhibited/knocked down primary rat Sertoli cells. PGE(2) production was measured by ELISA. Sertoli cell barrier function was determined by transepethelial resistance (TER) measurements in rat Sertoli cell primary cultures. BTB integrity in the cryptorchidism model was monitored by examining tracker dye injected into seminiferous tubules. MAIN RESULTS Down-regulation of CFTR accompanied by activation of NF-κB, up-regulation of COX-2 and down-regulation of TJ proteins, including ZO-1 and occludin, was observed in a cryptorchidism mouse model. BTB leakage revealed impaired BTB integrity in cryptorchid testes, confirming the destruction of TJs. The inverse correlation of CFTR and COX-2 was further confirmed in a mouse testis hyperthermia model and CFTR knockout mouse model. Culturing primary Sertoli cells at 37°C, which mimics the pathological condition of cryptorchidism, led to a significant decrease in CFTR and increase in COX-2 expression and PGE(2) production compared with the culture at the physiological 32°C. Inhibition or knockdown of CFTR led to increased COX-2 but decreased ZO-1 and occludin expression in Sertoli cells, which could be mimicked by PGE(2), but reversed by NF-κB or COX-2 inhibitor, suggesting that the regulation of TJs by CFTR is mediated by a NF-κB/COX-2/PGE(2) pathway. Inhibition of CFTR or administration of PGE(2) significantly decreased Sertoli cell TER. LIMITATIONS This study has tested only the CFTR/NF-κB/COX-2/PGE(2) pathway in mouse testes in vivo and in rat Sertoli cells in vitro, and thus, it has some limitations. Further investigations in other species, especially humans, are needed. WIDER IMPLICATIONS OF THE FINDINGS Our study may shed more light on one of the aspects of the complicated underlying mechanisms of defective spermatogenesis induced by cryptorchidism. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Basic Research Program of China (2012 CB944900), Natural Sciences Foundation of China (30870933), Li Ka Shing Institute of Health Sciences, the Focused Investment Scheme of the Chinese University of Hong Kong and Morningside Foundation. The authors declare no conflict of interest.     

Effects of body temperature on the expression and localization of meiosis-related proteins STRA8 and SCP3 in boar testes

Body temperature could lead to interruption of spermatogenesis, but the molecular mechanism was still unclear. Cryptorchidism was defined as the failure of testes to enter the scrotum, which exposed the testes to body temperature. Meiosis was a unique feature of germ cell development. Whether cryptorchidism damage the initiation of meiosis in boars had not been reported. The aim of this study was to determine whether spermatogonia in the cryptorchid testes entered into meiosis by detecting meiosis-related markers stimulated by retinoic acid gene 8 (STRA8) and synaptonemal complex protein 3 (SCP3). Three boars with spontaneous unilateral abdominal cryptorchidism were used. The testis located in the abdomen was cryptorchidism group, the scrotal testis of the same animal was used as control. HE results showed that only Sertoli cells, and a few spermatogonia remained in the seminiferous tubules, and no spermatids were seen compared with the control. Immunohistochemistry results showed that in both control and cryptorchidism group, STRA8 was mainly expressed in the nucleus of spermatogonia and spermatocytes. In control group, SCP3 was expressed in the nucleus of spermatocytes. In cryptorchidism group, SCP3 immunopositive cells were also observed. qRT-PCR and Western Blot results showed that the mRNA and protein levels of STRA8 and SCP3 were significantly decreased in cryptorchid boars. The expression of STRA8 and SCP3 in cryptorchidism suggested that spermatogonia could still enter meiosis in cryptorchid boars.     

Expression patterns of male germ cell markers in cryptorchid pig testes

Male germ cell apoptosis has been described in heat-damaged testes by cryptorchidism. In the present study, wild type pig testes were compared with cryptorchid testes via histological and immunohistological analyses. Spermatozoa were not detected in two cryptorchid testes and the diameters of seminiferous tubules were significantly reduced in cryptorchid pig testes compared with wild type pig testes. Cells expressing marker genes for undifferentiated spermatogonia, such as protein gene product 9.5 was significantly decreased in cryptochid pig testes. In addition, the numbers of cells expressing DEAD-box polypeptide 4 (VASA), synaptonemal complex protein 3, protamine, and acrosin (a biomarker of spermatocyte, spermatid, and spermatozoa) were significantly reduced in cryptochid pig testes. However, the number of vimentin-expressing Sertoli cells was not changed or was significantly increased in cryptorchid pig testes. This result indicates that male germ cells are specifically damaged by heat in cryptorchid pig testes and not Sertoli cells. These findings will facilitate the further study of spermatogenesis and the specific mechanisms by which cryptorchidism causes male infertility.     

Androgen aromatization in cryptorchid mouse testis

Estrogens play an important role in germ cell development. Therefore, we have studied expression patterns of aromatase that converts testosterone into estrogens in 2 recombinant inbred mouse strains that differ in efficiency of spermatogenesis. In order to show whether germ cells are a target for estrogens, estrogen receptors (ER)alpha and beta were localized as well. Adult male CBA and KE mice were made unilaterally cryptorchid to determine alterations in testicular steroidogenesis and spermatogenesis. Differences between control and cryptorchid testes have been studied with respect to (1) cellular sites of aromatase, the enzyme responsible for estrogen formation, (2) the presence of ERalpha and ERbeta in various types of testicular cells, and (3) steroidogenic activity in the testes. Additionally, unilaterally control testes of cryptorchid mice were compared with bilaterally descended testes. Histological or hormonal differences were not found between control testes of cryptorchid and untreated mice. In cryptorchid testes from both strains, degeneration of germ cells was observed as well as a decrease in size of the seminiferous tubules, whereas the amount of interstitial tissue increased, especially in testes of CBA mice. Using immunohistochemistry, aromatase was localized in Leydig cells and germ cells in both control and cryptorchid testes. Sertoli cells were immunopositive in control testes only. In cryptorchid testes of KE mice, aromatase was strongly expressed in spermatids, that were still present in a few tubules. Other cell types in tubules were negative for aromatase. In both control and cryptorchid testes of both mouse strains, ERalpha were present in Leydig cells only, whereas ERbeta were found in Leydig cells and in germ cells in early stages of maturation. In homogenates of testes of CBA control mice, testosterone levels were 3-fold higher than in those of control KE mice, whereas the difference in estradiol levels between both strains was small. Cryptorchidism resulted in decreased testosterone levels and increased estradiol levels. The results of the present study show functional alterations due to cryptorchidism in both mouse strains. Strong aromatase expression in germ cells in control and cryptorchid testes indicates an additional source of estrogens in the testis besides the interstitial tissue and the relevance of estrogen in spermatogenesis.     

Anti-MIC2 as a tool in examination of testicular biopsies.

MIC2 is a pseudoautosomal gene localized on X and Y chromosomes. The MIC2 gene product is a glycoprotein expressed on the cell membranes of a number of somatic cells, including Sertoli cells of the testis, but not on the cell membranes of germ cells. In cases of cryptorchidism, a testicular biopsy is recommended in order to evaluate future fertility potential. The spermatogonia are identified on histological sections and the number per tubular transverse section is compared with normal values for age. The patient is at 33-100% risk of subsequent infertility when the number of spermatogonia per tubular transverse section is lower than 1% of the lowest normal age-matched value. Besides Sertoli cells the seminiferous tubules in undescended testes contain only a few germ cells, and it may be difficult to pinpoint the germ cells in small biopsies. Especially in nonpalpable testes their number may be heavily reduced. A reliable identification of germ cells may also be difficult in cultures of testicular biopsies from undescended testes. Against this background, we tried the use of an immunohistochemical method with DAKO antibody to the MIC2 gene product (MIC2, 12 E7, code no. M3601) in order to obtain a "negative reaction" of germ cells, contrasting with the stained Sertoli cells. The material comprised: 44 specimens of testicular parenchyma taken at time of surgery for cryptorchidism from 24 cryptorchid boys with nonpalpable testes and 14 testicular biopsies from 13 cryptorchid patients with palpable testes which had been cultured in vitro for 7, 14 or 21 days. In all cases the immunohistochemical method with DAKO antibody to the MIC2 gene product was helpful for identification of Sertoli cells and germ cells, and we therefore recommend the use of anti-MIC2 in all testicular biopsies where it is difficult to pinpoint the germ cells.     

Decreased expression of cold-inducible RNA-binding protein (CIRP) in male germ cells at elevated temperature.

Physiological scrotal hypothermia is necessary for normal spermatogenesis and fertility in mammals. Cirp is a recently identified cold-inducible RNA-binding protein that is inducible at 32 degrees C in mouse somatic cells in vitro. Cirp is constitutively expressed in the testis of mouse and structurally highly similar to RBM1, a candidate for the human azoospermia factor. To elucidate the role played by Cirp in spermatogenesis, we investigated its expression levels during spermatogenesis and after heat stress. In the mouse testis, cirp mRNA was detected in the germ cells, and the level varied depending on the stage of differentiation. Also, a high level of Cirp protein was detected immunohistochemically in the nucleus of primary spermatocytes. Expression of Cirp was decreased in the GC-2spd(ts) mouse germ cell line when culture temperature was raised from 32 degrees C to 37 degrees C. When mouse testis was exposed to heat stress by experimental cryptorchidism or immersion of the lower abdomen in warm (42 degrees C) water, the expression of Cirp was decreased in the testis within 6 hours after either treatment. In human testis with varicocele analyzed immunohistochemically, germ cells expressed less Cirp protein than those in the testis without varicocele. These results demonstrated that CIRP expression is down-regulated at elevated temperature in male germ cells of mice and humans. Analysis of Cirp expression in the testes will help elucidate the molecular mechanisms leading to male infertility.     

Decreased expression of mouse Rbm3, a cold-shock protein, in Sertoli cells of cryptorchid testis

Physiological scrotal hypothermia is necessary for normal spermatogenesis and fertility in mammals. Human RNA binding motif protein 3 (RBM3) is structurally highly similar to the cold-inducible RNA-binding protein (Cirp), and both mRNAs are induced in human cells at the scrotal temperature (32 degrees C). We report here the cloning of mouse Rbm3 cDNA, which encoded an 18-kd protein with 94% identity in amino acid sequence to that of human RBM3. In the testis of adult mice, Rbm3 mRNA and protein were detected in Sertoli cells, but not germ cells, of seminiferous tubules at all stages. The expression was not observed in Sertoli cells of fetuses, but was observed in newborn and older mice. In the TAMA26 mouse Sertoli cell line, the Rbm3 expression level was increased or decreased within 12 hours after temperature shift from 37 degrees C to 32 degrees C or 39 degrees C, respectively. In contrast to Cirp, the cold-induced growth suppression of TAMA26 cells was not affected by suppression of the Rbm3 expression. When mouse testis was exposed to heat stress by experimental cryptorchidism, the level of Rbm3 was decreased in Sertoli cells. Rbm3 may play important roles distinct from those played by Cirp in spermatogenesis and cryptorchidism by regulating the gene expression in Sertoli cells.