Changes in the expression of P-cadherin in the normal, cryptorchid and busulphan-treated rat testis

Adhesion between Sertoli cells and germ cells is important for spermatogenesis. Cadherins are Ca(2+)-dependent transmembrane proteins that mediate cell-cell adhesion. The aim of this study was to compare the expression of P-cadherin in unilaterally cryptorchid and busulphan-treated rat testes using immunohistochemistry. The pattern of expression of P-cadherin in the seminiferous epithelium changed with the stage of the seminiferous epithelium. The membranes of round spermatids and membranes and cytoplasm of spermatocytes were strongly positive. Our experiments revealed that busulphan treatment (2 doses - 10 mg/kg of body weight - 21 days apart) and cryptorchism led to destructive changes in the structure of seminiferous tubules, together with the decrease in P-cadherin expression. The expression of P-cadherin disappeared in the spermatids segregated from the epithelium while segregated spermatocytes remained still positive for P-cadherin during the 3- to 11-day cryptorchid period. In busulphan-treated animals, the expression of P-cadherin was dependent on the presence or absence of the spermatocytes and spermatids in the tubules. Strong positivity for P-cadherin was observed in the spermatocytes that re-appeared in the regenerating seminiferous epithelium. We suggest that P-cadherin participates in the architecture of adherens junctions in testis, plays an important role in maintaining normal spermatogenesis and that cryptorchism and busulphan treatment lead to adherens junction disintegration.     

Involvement of ICAM‐1 in impaired spermatogenesis after busulfan treatment in mice

Expression of adherence proteins, such as P‐cadherin, has been identified in the normal testis and changed in impaired testis induced by alkylating agents. Intercellular adhesion molecule‐1 (ICAM‐1), a member of the immunoglobulin superfamily of cell adhesion molecules, is a constituent component of the blood–testis barrier and a multifunctional molecule in homeostasis of spermatogenesis. However, the distribution of ICAM‐1 in the testis of mice and expression changes after busulfan treatment remain unclear. In this study, ICAM‐1 immunoreaction was detected in Sertoli and germinal cells, particularly in spermatogonia, and elongating and elongated spermatids of normal testes. Accompanied with degeneration of spermatogenesis (decrease in testicular and epididymal weights, as well as loss of germ cells in histological morphology), ICAM‐1 expression declined significantly in the seminiferous tubules during a 4‐week experimental period, particularly in the first 2 weeks (40 mg kg^?1 busulfan, single injection). Compared with the control group, busulphan‐treated testes showed a significant increase in lipid peroxidation during weeks 1 and 2. Thus, ICAM‐1 may play an important role in the homeostasis of spermatogenesis, and busulfan treatment can lead to adhesion disintegration.     

Reversible effect of testosterone undecanoate injection on spermatogenesis in rats

Aim: To study the effect of testosterone undecanoate (TU) injection on spermatogenesis in rats. Methods: Twenty adult SD rats received vehicle or TU (8 mg/kg, 19 mg/kg or 025 mg/kg) injection, im, every 15 days for days, and another 38 animals received similar treatments for 130 days with half of them undergoing a recovery phase of 120 days (5 rats for each treatment). At the end of the treatment, testes were removed and the diameter of the seminiferous tubules and the number of late elongated spermatids ( steps 15 - 19 ) per testis were estimated with stereological methods as a measure of the spermatogenic efficiency. Results: Low dose (8 mg/kg) TU treatment virtually had no effect on spermatogenesis. A dose of 19 mg/kg slightly suppressed spermatogenesis 60 days after treatment, and severe suppression occurred after another 70 days of dosing. Spermatogenesis was completely recovered at the end of the recovery phase. Large dose (625 mg/kg) TU treatment did not significantly affect spermatogenesis and was well tolerated by animals. Conclusion: TU injection reversibly suppresses spermatogenesis in rats.     

Cisplatin-induced germ cell apoptosis in mouse testes

The purpose of this study was to investigate whether exposure of male mice to cisplatin induces apoptosis in male germ cells and the possible role of apoptosis in cisplatin-induced testicular damage. Forty-eight male BALB/c mice were divided into cisplatin and control groups. The mice from the cisplatin group received a single intraperitoneal injection of cisplatin of either 1, 5, or 10 mg/kg. The control group received a single intraperitoneal injection of saline alone. The testes were removed on days 1, 3, and 7 after cisplatin administration, respectively. Following histological examination, apoptotic indices (AIs) were measured within seminiferous tubules of the mouse testes by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. A low incidence of spontaneous apoptosis was observed in controls, particularly in spermatogonia and spermatocytes of the mouse testes. After cisplatin administration, both increased Als and decreased spermatozoa and spermatids were found in the seminiferous tubules of the mouse testes. Cisplatin-induced apoptosis was found in spermatogonia, spermatocytes, and spermatids of the mouse testes. In comparison to the control values, AIs increased 2.6- to 6.8-fold in cisplatin-treated mouse testes. AIs reached the highest level on day 1 following 1 mg/ kg, on day 3 following 5 mg/kg, and on day 7 following treatment of 10 mg/kg cisplatin. The study showed that cisplatin-induced germ cell apoptosis in the mouse testes was related to both the dose response and the time course of response. It is suggested that cisplatin-induced germ cell apoptosis may result in decreased spermatogenesis, and the higher dose of cisplatin may delay the occurrence of apoptosis in the mouse testes.     

Cloning and characterization of temperature-related gene TRS1

To investigate the mechanism of spermatogenesis arrest derived from heat treatment and to screen temperature-related genes involved in spermatogenesis, the authors analyzed the differences in gene expression between cryptorchid and scrotal testes in rats, and cloned a full-length cDNA named TRS1. In situ hybridization showed that TRS1 mRNA was mainly expressed in spermatocyte and round spermatids in testis. The expression level decreased in cryptorchid testis, suggesting that the lower scrotal temperature is a key factor in keeping the normal expression of TRS1. At the N-terminal of TRS1, there was a plecstrin homology (PH) domain signature. This PH domain has high similarity to that in PEPP2, a homosapien protein, which has a characteristic of binding phosphatidylinositol 3-phosphate via its PH domain in vitro. These findings suggest that TRS1 may be important in spermatogenesis and give clues for further research on the function of TRS1.     

Repeated interruptions of the testicular blood flow do not have long-term effects on spermatogenesis in the ram

Summary. The effect of repeated interruptions of the testicular blood flow on spermatogenesis was studied in mature Texel rams. Reversible interruption of the blood flow was achieved by an inflatable occluder, placed around the testicular artery at the level of the spermatic cord. In eight testes the blood flow was successfully interrupted six times for 1 h within 3 weeks and in 14 testes nine times for 1 h within 3 weeks. Nine weeks after the last blood flow interruption spermatogenesis was evaluated in histological sections of the testes. Both after six and nine blood flow interruptions a qualitatively complete epithelium was found in at least 90% of the seminiferous tubules. Cell counts in stages VII and VIII of the spermatogenic cycle revealed a slight decrease of spermatocytes and spermatids in the tubules with a complete epithelium after nine occlusions, which was only statistically significant for Preleptotene Spermatocytes. After six occlusions the numbers of all cell types were at or even slightly above control levels. These results show that repeated periods of ischaemia for 1 h do not result in conspicious long-term damage to spermatogenesis.     

Adenovirus-mediated p53 gene transfer to rat testis impairs spermatogenesis

The tumor suppressor protein p53 participates in normal cell differentiation as well as induction of programmed cell death. The authors investigated the effect of p53 overexpression on spermatogenesis by transferring p53 gene into the rat testes. Replication-deficient recombinant adenovirus vectors were constructed to include cytomegalovirus (CMV) promoter driving wild-type p53 (Ad-CMV-p53) or beta-galactosidase (Ad-CMV-beta-gal). Virus was delivered to cells of the tubules by slow retrograde injection through the rete testis. At 0, 4, 7, and 14 days, testes were removed, weighed, and analyzed histopathologically, including immunohistochemistry for p53, Bcl-2, Bax, and interleukin-1beta converting enzyme (ICE). Testicular weight was decreased in Ad-CMV-p53 group at 14 days after injection, while no change occurred in phosphate-buffered saline-injected controls or Ad-CMV-beta-gal-infected testes. Beyond 4 days, cell degradation in tubules interfered with immunohistochemical observation in the Ad-CMV-p53 group. At 4 days, p53 was expressed mostly in spermatocytes. Bax showed greater expression in the p53 group than in the control or Ad-CMV-beta-gal group. ICE, expressed mostly in spermatids, was more abundant in the p53 group than in controls. Overall, p53 overexpression in the testis impaired spermatogenesis.     

Cessation of Spermatogenesis in Juvenile Spermatogonia! Depletion (jsd/jsd) Mice

Background :
Mice homozygousforthe jsd (juvenilespermatogonial depletion) allele are sterile because they become azoospermic. The onset of such azoospermia was investigated by histologic analysis of sections of testes from jsd/jsd mice.
Method :
The testes removed from C57BL/6- jsd/jsd mice aged 3 to 10 weeks were examined microscopically.
Results :
At 3 weeks of age, spermatocytes were seen in most of the seminiferous tubules of jsd/jsd mice. However, the number of tubules that contained spermatids was significantly smaller than that counted in the wild-type mice. Since degenerative figures were not abundant in the jsd/jsd testes, the decreased number of spermatids found in the tubules suggested a longer duration of development from spermatocyte to spermatid in jsd/jsd mice. The abnormality extended to the development of type B spermatogonia, and a decrease in their number became apparent after 6 weeks of age in most of the jsd/jsd tubules. However, as early as 3 weeks of age, a few seminiferous tubules in jsd/jsd mice already contained only Sertoli cells and type A spermatogonia.
Conclusion :
It is assumed that the decrease in type B spermatogonia occurred at various ages and locations. The defect of spermatogenesis in jsd/jsd mice was attributable to aberrations in multiple steps of spermatogenesis.     

Gene expression changes of urokinase plasminogen activator and urokinase receptor in rat testes at postnatal stages

Aim： To investigate the gene expression changes of urokinase plasminogen activator （uPA）/urokinase receptor （uPAR） in rat testes at postnatal stages and explore the effects of uPA/uPAR system on the rat spermatogenesis. Methods： The mRNAs of uPA and uPAR in rat testes were measured by using real-time quantitative polymerase chain reaction （PCR） at postnatal days 0, 5, 10, 15, 21, 28, 35, 42, 49 and 56, respectively. Results： The tendencies of uPA and uPAR mRNA expression were similar at most postnatal stages except for Do. The expression of uPAR mRNA in rats testes was relatively higher than that of uPA at postnatal Do, and both were decreased until D21, increased obviously at postnatal D28, reached a peak at postnatal D35, then declined sharply at postnatal D42 and retained at a low level afterwards. Conclusion： The uPA/uPAR system may be strongly linked to spermiation and spermatogenesis via regulating germ cell migration and proliferation, as well as promoting the spermiation and detached residual bodies from the mature spermatids.     

The Anti-Reproductive Effects of Long Term Oral Administration of Cadmium on the Adult Male Rat

The toxic effects of prolonged oral administration of cadmium on gametogenic and endocrine function of testes of adult rats were investigated. The experimental animals received daily, for 3, 6, 12 or 15 months, pellets containing 8.8 mg or 88 mg of cadmium chloride per kg body weight.
The rats treated with the higher doses of cadmium for 12 and 15 months showed a marked reduction in absolute weight of testes accompanied by histological signs of impairment of seminiferous tubules. There were no necrotic changes but a number of cross-sections of seminiferous tubules were deprived of spermatocytes and spermatids, reaching about 50 per cent of the tubules in the rats treated with higher doses of cadmium. The appearance of histological changes in rats treated for 12 and 15 months correlated with cumulation step of cadmium in testes and with alterations in serum concentration of LH but not of testosterone. Therefore, we suppose that under these experimental conditions the impairment of seminiferous tubules was induced by the direct influence of cadmium on germinal epithelium beginning the moment when cadmium reaches an effectively toxic concentration in testis.     

Expression of hyperacetylated histone H4 during normal and impaired human spermatogenesis

Histone-to-protamine exchange in haploid spermatids is preceded by hyperacetylation of core histones resulting in decreased DNA-histone interaction. During normal spermatogenesis, immunohistochemistry with a polyclonal antihyperacetylated histone H4 antibody displayed a strong signal in nuclei of elongating spermatids and, in addition, spermatogonia. Quantitative analysis revealed 98.2 +/- 1.1% of immunopositive spermatids. The percentage of positive spermatids was significantly reduced in infertile men exhibiting at least qualitatively normal spermatogenesis (scores 10-8, 93.1 +/- 6.6%) and impaired spermatogenesis (scores 7-1, 74.9 +/- 23.4%). In seminiferous tubules showing spermatogenic arrest at the level of round spermatids, only 59.5 +/- 16.5% of spermatids were immunopositive for hyperacetylated histone H4. These data demonstrate that the decrease of histone acetylation in spermatids associated with impaired spermatogenesis corresponds with the well known reduction of protamine expression in these cells and confirms the essential role of histone hyperacetylation for correct histone-to-protamine exchange. In seminiferous tubules exhibiting round spermatid maturation arrest, there was an additional signal in nuclei of spermatocytes, suggesting that premature hyperacetylation of histone H4 may result in precocious histone-to-protamine exchange followed by infertility. This is in accordance with data from transgenic mice, where it has been demonstrated that premature expression of protamine-1 results in precocious chromatin condensation followed by sterility.     

Histology of artificial cryptorchid testes followed by orchiopexy in pubertal rats

Artificial bilateral cryptorchidism was induced in 4 groups of pubertal male albino rats for different periods. Left orchiopexy and right orchiodectomy were performed. The left testes were orchidectomized after 70 days in the scrotum, the necessary period for possible recovery of spermatogenesis. The comparative histology of both testes showed that the longer the period of cryptorchidism, the more histological degeneration could be observed. However, after 70 days of recovery, only the 4 days cryptorchid testes succeeded in recovery and reorganization of spermatogenesis in the majority of the seminiferous tubules.     

Study on changes of testicular AQP7mRNA and histology in varicocele rats

Experimental varicocele was created in male rats by partial lig-ation of left renal vein (VC) and control rats received a sham oper-ation (SO). Changes in AQP7mRNA expression and testicularfunction were observed. The results are as following: 1.AQP7mRNA expression in left testis of VC rats decreased signifi-cantly, while increased in the right, when compared with SO. 2.Weights of left testis in VC rats were significantly lower than thosein SO (P<0.05) and lower than those of the right (P>0.05);no difference was found between right testes in two groups. In VC,especially in left testes, there were sloughing spermatogenous cellsin slight and moderate atrophied seminiferous tubules, and edema inintestitial tissue as well. It suggests that left varicocele results indysfunction of spermatogenesis in rat testes, especially in the lefttestis. Obvious difference in AQP7mRNA expression suggestedchanges of water metabolism might be one of reasons for distur-bance of spermatogenesis, while active metabolism in righ     

Developmental expression of c-kit protooncogene in the rat testis

IntroductionInmammalianembryos,thegermcelllinebeginswithprimordialgermcelIs,andinmales,primordialgermcellsbecomegono-cytes,thece1lprecursorsofthespermatogoni-a.ThedevelopmentofanormaltestisdependsupontheproliferationofprimordialgermcellsandtheiraggregationwithSertolicellprecur-sorsLl:.Theseeventshavebeenshowntobeassociatedwiththeexpressionofthec-kitProtooncogenemappedtothe"whitespottinglocus(W)~ofthemouse[2,3j.Thec-kitPro-tooncogeneencodesatransmembranetyrosinekinasereceptor(4,5).Thestructu…     

胱蛋白酶抑制剂相关的附睾精子发生基因在不同发育阶段小鼠睾丸和附睾中的表达

目的 :研究胱蛋白酶抑制剂相关的附睾精子发生 (Cres)基因在生后不同发育阶段小鼠睾丸及附睾中的表达规律。　方法 :采用半定量RT PCR方法检测CresmRNA在生后 14、2 0、2 2、2 8、35、4 9、70、4 0 0d小鼠睾丸及附睾中的表达变化。　结果 :Cres基因在 14d小鼠睾丸和附睾中呈低水平表达 ,随着小鼠的生长发育 ,CresmRNA的表达量逐渐升高。在 70d小鼠睾丸和 4 0 0d小鼠附睾中 ,CresmRNA的表达量达到峰值。　结论 :Cres基因在生后不同发育阶段小鼠睾丸及附睾中呈现明显的规律性表达 ,可能参与精子发生、成熟过程的调控。