Correlation of sperm DNA fragmentation index with age and semen parameters in infertile men / 中华男科学杂志

<p><b>Objective</b>To explore the correlation of the sperm DNA fragmentation index (DFI) with age, sperm concentration and sperm motility in infertile men.</p><p><b>METHODS</b>We collected semen samples from 531 infertile males in our hospital from January 2016 to June 2017. We determined the semen parameters using the computer-assisted semen analysis system, measured the sperm DFI by sperm chromatin structure assay, and analyzed the correlation of the sperm DFI with the age, sperm concentration and sperm motility of the patients.</p><p><b>RESULTS</b>With the increase of age, the infertile males showed a significantly decreased proportion of the sperm with a DFI ≤15% and elevated proportion of the sperm with a DFI ≥25%, with a positive correlation between age and sperm DFI (r = 0.653, P < 0.01). With the increase of sperm concentration and motility, however, the proportion of the sperm with a DFI ≤15% was remarkably increased while that of the sperm with 15%<DFI<25% and ≥25% markedly reduced, both sperm concentration and motility negatively correlated with the sperm DFI (r = －0.246, P < 0.01 and r = －0.406, P < 0.01).</p><p><b>CONCLUSIONS</b>The sperm DFI is significantly correlated with age, sperm concentration and sperm motility, and therefore can be used as an important index for the evaluation of semen quality. A comprehensive analysis of the sperm DFI and semen parameters may contribute to an accurate assessment of male fertility.</p>

Literature research of the adverse reactions of zhengqinfengtongning injection and its synergism and toxicity reducing effects / 中国药学杂志

Search Chinese search CNKI, VIP full-text database and MML (Metadata center of Medical Literature) about the document of the Zhengqingfengtongning Injection adverse drug reaction and the effect of Zhengqingfengtongning Injection in enhancing efficacy and reducing toxicity of chemotherapy. To analyze the correlation between dosage, mode of administration, time and ADR occurrence. To summarize the synergistic and attenuated drugs, and explore the mechanism of interaction between Zhengqingfengtongning Injection and these synergistic and attenuated drugs. Discuss the mechanism of Zhengqingfengtongning Injection ADR and the mechanism of Zhengqingfengtongning Injection's synergism and attenuation, and preventive measures of the ADR. The purpose of this paper is to provide evidence basis for clinical safety of the application of Zhengqingfengtongning Injection.

Expression of Attractin in male reproductive tract of human and mice and its correlation with male reproduction / 华中科技大学学报（医学）（英德文版）

The expression of Attractin mRNA and protein in testis and semen of human and male mice was investigated. Human testis and semen samples were all collected from Reproductive Center of Renmin Hospital, Wuhan University in December, 2012. Testis samples were collected from 7 cases of obstructive azoospermias when they were subjected to diagnosed testis biopsy, and 30 normal human semen samples were obtained from those cases of semen analysis. Adult mice testis tissues were obtained from 10 2-month-old male BALB/c mice, and 60 male mice at different ages were classified into 10 groups (day 1, 5, 10, 15, 21, 28, 35, 42, 56, and 120 respectively, n=6 each). The expression of Attractin mRNA and protein in testis was detected by RT-PCR and Western blotting respectively. Human semen samples were centrifuged into sperm plasma (SP) and sperm extract (SE), and mice sperm samples were collected from the epididymis of 10 adult male BALB/c mice. Western blotting was used to determine the Attractin protein expression level. Attractin mRNA and protein were expressed in the testis of both patients with obstructive azoospermias and adult Bcl/B mice. Quantitative RT-PCR revealed that no Attractin mRNA was detectable in day 1 male BALB/c mice group. The Attractin mRNA and protein levels were low on the day 10, and increased with age until day 56. On the day 120, the expression levels of Attractin were decreased. As for human semen samples, Attractin protein was expressed in both SP and SE, but didn't exist in samples from the epididymis of male BALB/c mice. It was suggested that Attractin acted as a novel active substance and was involved in male reproduction in both human and BALB/c mice, but it exerted a different expression profile in different mammal species.

Expression of Attractin in male reproductive tract of human and mice and its correlation with male reproduction / 华中科技大学学报（医学）（英德文版）

The expression of Attractin mRNA and protein in testis and semen of human and male mice was investigated. Human testis and semen samples were all collected from Reproductive Center of Renmin Hospital, Wuhan University in December, 2012. Testis samples were collected from 7 cases of obstructive azoospermias when they were subjected to diagnosed testis biopsy, and 30 normal human semen samples were obtained from those cases of semen analysis. Adult mice testis tissues were obtained from 10 2-month-old male BALB/c mice, and 60 male mice at different ages were classified into 10 groups (day 1, 5, 10, 15, 21, 28, 35, 42, 56, and 120 respectively, n=6 each). The expression of Attractin mRNA and protein in testis was detected by RT-PCR and Western blotting respectively. Human semen samples were centrifuged into sperm plasma (SP) and sperm extract (SE), and mice sperm samples were collected from the epididymis of 10 adult male BALB/c mice. Western blotting was used to determine the Attractin protein expression level. Attractin mRNA and protein were expressed in the testis of both patients with obstructive azoospermias and adult Bcl/B mice. Quantitative RT-PCR revealed that no Attractin mRNA was detectable in day 1 male BALB/c mice group. The Attractin mRNA and protein levels were low on the day 10, and increased with age until day 56. On the day 120, the expression levels of Attractin were decreased. As for human semen samples, Attractin protein was expressed in both SP and SE, but didn't exist in samples from the epididymis of male BALB/c mice. It was suggested that Attractin acted as a novel active substance and was involved in male reproduction in both human and BALB/c mice, but it exerted a different expression profile in different mammal species.

Advances in the studies of cell-free seminal DNA / 中华男科学杂志

Cell-free DNA, also referred to as extracellular DNA, has been detected in many kinds of human body fluids, including blood plasma, urine, cerebrospinal fluid, bronchoalveolar lavage fluid, amniotic fluid, and seminal plasma. At present, cell-free DNA has been reported widely as promising noninvasive biomarkers for disease diagnosis and research. Recent years have witnessed some progress in the studies of the general characteristics of cell-free DNA, such as its concentration, extent of molecular weight, origin and existing forms, as well as in its clinical application. Cell-free seminal DNA has been proposed as promising noninvasive biomarkers for the studies and diagnosis of male idiopathic infertility, and the early diagnosis, treatment evaluation and outcome prediction of testicular germ cell tumors and prostatic cancer. This review summarizes the general characteristics and biological functions of cell-free DNA, and outlines the research status and application perspective of cell-free seminal DNA.

Detecting testis- and epididymis-specific methylated promoters in human cell-free seminal DNA by MeDIP-qPCR / 中华男科学杂志

<p><b>OBJECTIVE</b>To establish a method of methyl-DNA immunoprecipitation (MeDIP)-real time quantitative PCR (qPCR) for detecting the promoter methylation level in cell-free seminal DNA (cfsDNA).</p><p><b>METHODS</b>We obtained cfsDNA samples from 6 normozoospermia men (the NZ group) and 6 post-vasectomy patients (the PV group), and mixed the samples from different individuals of each group, respectively. Then we made DNA fragments by ultrasonication, separated the methylated DNA fragments by MeDIP, and determined the methylation level of the promoters in cfsDNA by qPCR.</p><p><b>RESULTS</b>The methylation levels of the promoters PRAME, PEG10, MORC1, GML, HOXA5, DNMT3L, SNURF, MSH4, DAZ1 and CLPB were 14.93, 2.64, 0.69, 2.66, 17.50, 21.10, 5.98, 2.28, 13.50 and 3.86%, respectively, in the NZ group, obviously lower than 121.25, 73.62, 16.25, 42.90, 76.74, 112.40, 59.79, 25.85, 91.90 and 64.53% in the PV group. The results of MeDIP-qPCR for the methylation of PRAME, MORC1, GML, HOXA5, DNMT3L, SNURF, MSH4 and DAZ1 were coincident with the results of genome-wide promoter methylation microarray.</p><p><b>CONCLUSION</b>MeDIP-qPCR can quantitatively measure the promoter methylation level in cfsDNA, and effectively determine the testis- and epididymis-specific methylated promoters in human semen.</p>

Progress in researches on male immunocontraception / 中华男科学杂志

The ideal goal of male immunocontraception is to develop a safe, effective, convenient, acceptable and reversible contraceptive vaccine. Current studies mainly focus on screening the most suitable target antigens from reproductive hormones and sperm functional proteins for the development of immuno contraceptive vaccines. The vaccine targeting reproductive hormones has not been widely used due to its different degrees of side effects and complicated operation. Recent studies show the practicability and applicability of the immuno contraceptive vaccine targeting sperm specific antigens, but its development is confronted with many challenges, such as how to select appropriate target antigens, how to enhance the immunogenicity of the vaccine, how to choose appropriate drug-delivery ways, how to reduce its side effects, and how to decrease its cost.

Association of CFTR gene polymorphism with congenital bilateral absence of vas deferens in ethnic Han Chinese patients / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association between a 5T polymorphism in intron 8 of cystic fibrosis transmembrane conductance regulator (CFTR) gene and congenital bilateral absence of vas deferens (CBAVD) in Han Chinese males.</p><p><b>METHODS</b>Genomic DNA from 33 individuals with CBAVD and 99 azoospermic males with CBAVD were recruited. The 5T polymorphism was detected with PCR, TA cloned and sequenced.</p><p><b>RESULTS</b>CFTR gene mutations were identified in 17 (51.5%) of patients with CBAVD. In 3 patients (17.6%), the mutations were identified on both alleles. Nine CFTR gene mutations (9.1%) were detected in 99 azoospermic patients, for whom none had mutations on both alleles.</p><p><b>CONCLUSION</b>This study has confirmed molecular heterogeneity of CFTR mutations in CBAVD. For CBAVD patients without 5T mutations, other changes may be found in the same gene.</p>

Cell-free RNA in human seminal plasma: characteristics and potential application / 中华男科学杂志

Cell-free RNAs (cfRNAs), including mRNA and microRNA, are transcripts existing outside cells. These extracellular RNAs have been detected in many kinds of human body fluids and reported as promising noninvasive biomarkers for disease diagnosis and research. Recent studies discovered the presence of cfRNAs in human seminal plasma and revealed its general characteristics. Cell-free seminal RNA has been proposed as a novel noninvasive biomarker for male infertility and forensic identification. This review focuses on the general characteristics, current application, and perspective of cfRNAs.

Literature research of the hepatotoxicity of glucoside tripterygium total and its synergism and toxicity reducing effects / 中国中西医结合杂志

Correlated literatures of the liver injury induced by glucoside tripterygium total (GTT) and of its synergism and toxicity reducing effects were retrieved to study the correlation between the dosage, the time point of GTT and the liver injury. The monomer or active ingredients of animals and plants with the hepatoprotective effect were included. The mechanisms of action between GTT and these drugs were analyzed. The mechanism for GTT induced liver injury and its synergism and toxicity reducing mechanisms, as well as the preventive measures were discussed, thus providing evidence-based basis for safe clinical application of GTT.

Expression of NOSTRIN in the testis tissue of azoospermia patients / 中华男科学杂志

<p><b>OBJECTIVE</b>To determine the expressions of endothelial nitric oxide synthase traffic inducer (NOSTRIN) and endothelial nitric oxide synthase (eNOS) in the testis tissue of azoospermia patients, and investigate their correlation with the pathogenesis of azoospermia.</p><p><b>METHODS</b>We detected the expressions of NOSTRIN and NOSTRIN mRNA by immunohistochemistry and RT-PCR respectively, determined the activity of eNOS by spectrophotometry, and measured the stable metabolic end product NO, NO2- / NO3-, by nitrate reductase assay in the testis tissues of 17 patients with idiopathic azoospermia (the azoospermia group) and 10 normal men (the normal group).</p><p><b>RESULTS</b>NOSTRIN and NOSTRIN mRNA were expressed in the spermatogonia, sertoli cells, stromal cells and vascular endothelial cells, more lowly in the azoospermia than in the normal group (0.312 +/- 0.076 versus 0.793 +/- 0.082, P < 0.01). The activity of eNOS was significantly increased in the idiopathic azoospermia patients ([33.727 +/- 3.58] U/mg) compared with the normal men ([17.69 +/- 3.84] U/mg) (P < 0.01). The level of NO2- / NO3- was significantly higher in the azoospermia than in the normal group ([48.56 +/- 8.49] micromol/L versus [25.37 +/- 9.61] micromol/L, P < 0.01). The expression of NOSTRIN showed a significant negative correlation with the activity of eNOS (r = -0.57, P < 0.01) as well as with the level of NO2- / NO3- (r = -0.61, P < 0.01) in the testis tissue of the idiopathic azoospermia patients.</p><p><b>CONCLUSION</b>The expression of NOSTRIN is decreased, while the activity of eNOS and the level of NO2- / NO3- increased in the testis tissue of azoospermia patients, which may be associated with the pathogenesis of azoospermia.</p>

Genetic defect in Chinese azoospermic patients and their relationship with reproductive hormones / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the incidence of abnormal karyotypes and Y chromosome microdeletion in Chinese men with azoospermia, and the relationship with reproductive hormones.</p><p><b>METHODS</b>Four hundred and eighty nine cases of azoospermic patients and 20 fertile men were studied. Karyotypes and Y chromosome microdeletion were analyzed by G-banding and mutiplex polymerase chain reaction, respectively. Chemiluminescene immunoassay technique was applied to measure the serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), and prolactine (PRL).</p><p><b>RESULTS</b>Chromosome abnormalities were found in 102 out of 489 azoospermic patients (20.86%), among them 86 (84.31%) cases had sex chromosome abnormalities, with 73 cases being Klinefelter syndrome. Y chromosome microdeletions were detected in 58 (11.86%) cases out of the 489 patients, and deletion of the AZFc region was the leading group (63.8% of all deletions), followed by AZFbc (19.0%), AZFabc (10.3%), AZFb or AZFa (3.4%). FSH, LH levels were significantly increased and T level was decreased in azoospermic patients compared with the fertile men group (P<0.01). Furthermore, in the azoospermic patients with Klinefelter syndrome or AZFabc microdeletions, FSH and LH levels were increased more significantly, and were statistically different from azoospermic patients with normal karotype or without Y chromosome microdeletion (P<0.05).</p><p><b>CONCLUSION</b>In the Chinese men with azoospermia, the incidence of abnormal karyotype and Y chromosome microdeletion were similar to those described previously in other populations. In azoospermia with Klinefelter syndrome or AZFabc microdeletions, FSH and LH levels increased markedly indicating the protracted stimulation of gonadotrophs due to lack of androgen feedback.</p>

The effect of the split of sperm nuclei on the yield of human sperm RNA / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the effect of the split of sperm nuclei on the yield of RNA from human sperm.</p><p><b>METHODS</b>Human sperm were purified by two sequential centrifugations through 40:80 discontinuous gradients of Percoll. Human leukocytes separated from peripheral blood were used as the control. Total RNAs from purified sperm and leukocytes were extracted with both TRIzol and RNeasy Kit. The RNAs from equal number of cells were reverse-transcribed, and quantified by the levels of beta-ACTIN mRNA, which were evaluated by real time polymerase chain reaction.</p><p><b>RESULTS</b>TRIzol failed to digest majority of sperm nuclei even the incubation time was prolonged to 1 h, while no sperm nucleus was found under the light microscope after 1 min digestion with RLT buffer of the RNeasy Kit. Both reagents can digest the nuclei of human leukocytes well. The amount of RNA per 10(6) sperms isolated with RNeasy Kit (149.8+/-24.5 ng) was 4-fold higher (P=0.01) than that extracted with TRIzol (35.5+/-4.0 ng per 10(6) spermatozoa; n=3). The similar yields of the leukocyte RNAs extracted with RNeasy Kit and TRIzol [(765.5+/-229.8) and (958.8+/-201.0) ng per 10(6) cells respectively; n=3, P=0.168] excluded the possibility of different efficacy of these two reagents in RNA isolation.</p><p><b>CONCLUSION</b>The split of sperm nuclei is important to the yield of RNA in the human sperm RNA extraction. The nucleus may be the major area for human sperm RNA repositories.</p>

A novel class of testis-specific small RNAs: piRNAs / 中华男科学杂志

Eukaryotes produce various types of 19-30 nt small RNAs, which act as guides to the regulation of gene expressions, such as mRNA degradation and translational repression. The Argonaute family members related to small RNA functions fall into 2 subfamilies. One is the AGO subfamily, whose 4 members distribute widely, confirmedly bind to miRNAs and siRNAs and inhibit the expression of target mRNAs through a pathway like RNA interference. The other is the PIWI subfamily, including PIWI, Aubgine (AUB) and AGO3, exclusively expressed in the testis. Recently, four research groups have isolated a new class of small RNAs from the mammalian testis, which interacts with the PIWI subfamily, hence named piwi-interfering RNAs (piRNAs), and is suggestive of an important role in spermatogenesis.

Y chromosome microdeletions of 664 Chinese men with azoospermia or severe oligozoospermia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the incidence and location of Y chromosome microdeletions in Chinese azoospermia and severe oligozoospermia, as well as the relationship between the deletion region and testicular phenotype.</p><p><b>METHODS</b>Semen samples or blood samples were collected from 664 Chinese patients (584 with azoospermia and 80 with severe oligozoospermia). DNA was extracted by incubating cells with a lysis buffer containing polymerase chain reaction (PCR) buffer and proteinase K, and was assayed for deletion of 15 sequence tagged sites (including 6 loci recommended by European Academy of Andrology and European Molecular Genetics Quality Network (EAA/EMQN) distributed in AZFa, AZFb and AZFc by 4 multiplex PCRs. The histological phenotypes of testes of some azoospermic patients harboring Y chromosome microdeletion were studied by fine needle aspiration.</p><p><b>RESULTS</b>Sixty-six (11.3%) cases of microdeletions were found in the 584 patients with azoospermia, and deletions of AZFc region are the leading group (72.7% of all deletions), followed by AZFbc (13.6%), AZFabc (6.1%), AZFb (4.5%) and AZFa (3.0%). In the 80 men with severe oligozoospermia, 10 (12.5%) cases of AZFc microdeletions were detected. While azoospermia (n=19) with AZFc region deletion showed variable testicular phenotype, deletions of AZFb+c and AZFa+b+c (n=7) resulted in severe impaired spermatogenesis characterized by Sertoli cell only syndrome and spermatogenic arrest at spermatogonia.</p><p><b>CONCLUSION</b>In the Chinese men with azoospermia and severe oligozoospermia, the incidence of Y chromosome microdeletions and the frequency of the deletions of the three AZF regions are similar to those described previously in other populations. Massive deletions of AZFb+c and AZFa+b+c impair spermatogenesis severely.</p>

Gene expression changes of urokinase plasminogen activator and urokinase receptor in rat testes at postnatal stages / 亚洲男科学杂志(英文版)

<p><b>AIM</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>The tendencies of uPA and uPAR mRNA expression were similar at most postnatal stages except for D(0). The expression of uPAR mRNA in rats testes was relatively higher than that of uPA at postnatal D(0), and both were decreased until D(21), increased obviously at postnatal D(28), reached a peak at postnatal D(35), then declined sharply at postnatal D(42) and retained at a low level afterwards.</p><p><b>CONCLUSION</b>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.</p>

Establishment of an animal model of azoospermia in male mice / 中华男科学杂志

<p><b>OBJECTIVE</b>To establish a stable animal model of azoospermia in male mice.</p><p><b>METHODS</b>Two groups of mice, with 30 in each, were intervened respectively by chemotherapy (intraperitoneal injection of Busulfan and Cyclophosphamide) and subcutaneous injection of Estradiol. At different times after the injection, the microscopic structures of the seminiferous tubules of both groups were observed and compared. The recovery of the germ cells in the seminiferous tubules was also evaluated after the termination of the intervention.</p><p><b>RESULTS</b>A stable animal model was established by chemotherapeutic method with Busulfan and cyclophosphamide, while the model constructed by muscle injection of Estradiol was not stable.</p><p><b>CONCLUSION</b>Compared with estrogen injection, chemotherapeutic intervention is a reliable method for constructing an animal model of azoospermia in male mice.</p>

Effect of urokinase-type plasminogen activator on the mitochondrial membrane potential of mouse capacitated-spermatozoa in vitro / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the mechanism of uPA improving sperm capacitation by investigating the effect of uPA on the mitochondrial function of mouse capacitated-sperm in vitro.</p><p><b>METHODS</b>Mitochondrial function of mouse capacitated-spermatozoa was evaluated through the assessment of mitochondrial membrane potential using JC-1 performed by flow cytometer and fluorescent microscope respectively. The experiment and the control groups were designed according to the presence or absence of uPA, each divided into 5 subgroups based on the different time of uPA treatment (or BWW in the control groups) at 0, 5, 15, 30 and 60 min respectively.</p><p><b>RESULTS</b>(1) Compared with that at 0 min, the mean fluorescence intensity of JC-1 within the spermatozoal body and the percentage of orange-red colored spermatozoa in the experiment group were increased significantly at 5 and 15 min respectively after uPA incubation (P < 0.05). (2) The mean fluorescence intensity of JC-1 within the spermatozoal body at 15, 30 and 60 min and the percentage of orange-red colored spermatozoa at 5 and 15 min in the group were significantly higher than those in the control group (P < 0.05).</p><p><b>CONCLUSION</b>uPA could increase the mitochondrial membrane potential of mouse capacitated-spermatozoa in vitro, and maintain it at a high level for a certain period of time. By enhancing sperm mitochondrial function, uPA may provide sufficient energy for capacitated-spermatozoa to increase their motility and change their motor pattern, which might be one of the therapeutic mechanisms of uPA on male infertility.</p>

Optimization of real time RT-PCR system for the quantitative estimation of CatSper1 mRNA levels in human and mouse mature spermatozoa / 中华男科学杂志

<p><b>OBJECTIVE</b>To establish and optimize a real time RT-PCR system for determining the transcript levels of CatSper1 in human and mouse mature spermatozoa containing microamount of RNA.</p><p><b>METHODS</b>Total RNA of human and mouse mature spermatozoa was isolated by using TRIzol reagent and reversely transcribed to complementary DNA respectively. Primers for real time RT-PCR were designed in the homologous area of the human and mouse CatSper1 mRNAs. Human sperm complementary DNA was used as the template to the optimize the conditions for SYBR Green I real time RT-PCR, including annealing temperature, Mg2+ concentration, fluorescence measurement temperature and the ratio between forward and reverse primers. The standard curve was constructed with serial dilutions of complementary DNA from human sperm to ascertain the amplification efficiency of SYBR Green I real time PCR and to quantitate the CatSper1 mRNA levels in the human and mouse mature spermatozoa.</p><p><b>RESULTS</b>The optimal conditions for real time RT-PCR, that is, annealing temperature, Mg2+ concentration and the ratio between forward and reverse primers were 63 degrees C, 3.0 mmol/L and 1:1 respectively. The fluorescence measurement temperature was 88 degrees C. The standard curves were Y = -3.402 log (X) + 25.99 and Y = -3.409 log(X) + 24.09 in the human sperm cDNA and mouse sperm cDNA as the template, with amplification efficiency of 96.8% and 96.5% respectively. The R2 value (an indicator of the quality of the fit of the standard curve to the standard data points plotted) of both standard curves was 0.998. The CatSper1 mRNA levels in the human and mouse mature spermatozoa could be determined according to the standard curve.</p><p><b>CONCLUSION</b>The general RT-PCR system, by adding SYBR Green I and optimizing its conditions, could be used to quantitate the mRNA levels in both human and mouse mature spermatozoa.</p>

Peroxidative damage induced by cumene hydroperoxide in testis and epididymis of rats in vivo / 中华男科学杂志

<p><b>OBJECTIVE</b>To establish an oxidative stress model induced by cumene hydroperoxide (cHP) in testis and epididymis of rats in vivo, and to understand the peroxidative damage of oxidative stress in testis, epididymal sperm and its propensity to induce nuclear DNA damage during spermatogenesis and sperm maturation in vivo.</p><p><b>METHODS</b>An organic hydroperoxide, cHP, 70% aqueous, diluted by 0.9% NaCl, was employed as model prooxidant. Ninety-day-old male Wistar rats were divided into a control and three cHP groups, and were administered intraperitoneally 0, 1/10, 1/6 and 1/4 LD50 cHP per day respectively at a dose of 2 ml/kg, for 7 consecutive days and were observed for any toxic symptoms and mortality. Twenty-four hours after the last dose, rats were sacrificed and induction of oxidative stress was ascertained by monitoring the degree of lipid peroxidation expressed as nano molar of malondialdehyde (MDA) in testicular homogenate and epididymal sperm. Nuclear DNA damage in testes and epididymal sperms was determined by comet assay. Motility of caudal sperms was counted and the morphology of testes and epididymis was observed under light microscope.</p><p><b>RESULTS</b>Rats of cHP administered groups were less vigorous than those of the control, but there were not death of rats during treatment. 1/10 LD50 per day for 7 consecutive days resulted in only a marginal increase in testicular MDA levels. However, 1/6 and 1/ 4 LD50 per day for 7 days of cHP administered to adult rats induced marked oxidative stress in testis and epididymal sperms as evidenced by a marked increase in MDA or nuclear DNA damage in testis and caput sperms, as well as significant decreases both in the body weight-and motility of caudal sperms. While the nuclear DNA damage caput sperms of 1/6 and 1/4 LD50 cHP administered rats increased significantly, nuclear DNA damage in caudal sperms showed no treatment related alterations.</p><p><b>CONCLUSION</b>Oxidative stress in testis and epididymal sperms can be safely induced by applying multiple doses of cHP (1/6 and 1/4 LD50 per day for seven consecutive days). DNA damage caused by cHP induced oxidative stress may occurred mainly in testes.</p>