Ikuo Miyagawa

Effects of Smoking on Testicular Function, Semen Quality and Sperm Fertilizing Capacity

PURPOSE The effects of smoking on testicular function and sperm physiology were studied. MATERIALS AND METHODS Left testicular biopsy was performed in 49 smokers and 28 nonsmokers. Seminal specimens from these men were analyzed. RESULTS Testosterone levels in the left testicular vein, left testicular androgen-binding protein secretion rate (in vitro), sperm motility, percentage of morphologically normal spermatozoa, sperm morphometric parameters and outcome of sperm function tests were significantly lower (p < 0.05) in smokers than in nonsmokers. CONCLUSIONS Morphological sperm abnormalities due to secretory dysfunction of the Leydig and Sertoli cells may be the cause of impaired sperm fertilizing capacity in smokers.

Reproductive capacity of the nucleus of the male gamete after completion of meiosis

PurposeOur purpose was to investigate the possibility of achieving fertilization and subsequent normal embryonic development by injecting round spermatid nuclei into rabbit oocytes.ResultsTwo- to four-cell-stage embryos developed after round spermatid nuclear injections into rabbit ooplasma could further develop in vitro up to the expanding blastocyst stage or in vivo up to complete gestation.ConclusionThe current findings show that the haploid set of chromosomes of round spermatid can pair with the chromosomes of the ootid to participate in complete fertilization and subsequent embryonic and fetal development. In addition, we suggest that postmeiotic modifications of the round spermatid are not required for the pairing of male gamete chromosomes with those of the ootid.

Effects of smoking on testicular function and fertilizing potential in rats

Abstract We evaluated the effects of smoking on testicular function and fertilizing potential in rats. Twenty rats (group A) were exposed to the smoke of 20 cigarettes for 1 h per day. Ten rats (group B) were exposed to the smoke of 40 incense sticks for 1 h per day, and an additional 10 rats served as a control group (group C). After 10 weeks of daily exposure, serum levels of nicotine and cotinine were assessed, and a mating test was conducted. Five days later, serum concentrations of testosterone before and after human chorionic gonadotropin (hCG) stimulation, gonadotropins, and epididymal sperm content and motility were evaluated. In addition, in vitro fertilization was carried out. Nicotine and cotinine were detected in group A, but not in groups B and C. Basal serum testosterone and gonadotropin concentrations did not differ significantly among the three groups, but the testosterone response to hCG stimulation was significantly lower in group A than in groups B and C. Group A showed significant reductions in epididymal sperm content and motility, and in fertility in vivo and in vitro. These findings suggest that smoking leads to a secretory dysfunction of the Leydig cells, and also a deficiency in sperm maturation and spermatogenesis. In addition, smoking has a detrimental effect on sperm fertilizing potentials in vivo and in vitro.

Effects of paternal cigarette smoking on testicular function, sperm fertilizing capacity, embryonic development, and blastocyst capacity for implantation in rats

Summary. We evaluated the effects of paternal smoking on testicular function, sperm fertilizing capacity, embryonic development, and blastocyst capacity for implantation. Rats of group A were exposed to cigarette smoke for 10 weeks. Rats of group B were exposed to the smoke of incense sticks for 10 weeks. Rats of group C served as a control group. Rats of group D were exposed to cigarette smoke for 7 weeks only. Experimental period was 10 weeks in all groups. At the end of the experimental period serum testosterone responses to human chorionic gonadotropin stimulation, andro‐gen‐binding protein activity in testicular cytosols, epididymal sperm motility, and oocyte fertilization rate, oocyte cleavage rate, and blastocyst development rate after in vitro fertilization (IVF) trials were significantly smaller in group A compared with groups B and C. In contrast, fertilization rate, cleavage rate, and blastocyst development rate after intracytoplasmic sperm injection (ICSI) procedures were not significantly different among groups A, B, C, and D. Both after IVF trials and ICSI techniques, the proportion of the alive offspring to the number of transferred oocytes was significantly smaller in group A than in groups B and C. Cigarette smoke‐exposure results in a secretory deficiency of Leydig and Sertoli cells leading to an impaired epididymal sperm maturation process and diminished capacity of spermatozoa to penetrate oocytes. In addition paternal cigarette smoke exposure affects the embryonic ability for implantation.

Ooplasmic round spermatid nuclear injection procedures as an experimental treatment for nonobstructive azoospermia

AbstractPurpose: Our objective was to apply ooplasmic round spermatid nuclear injections for the treatment of nonobstructive azoospermia. Materials: Participants were nine azoospermic men who had previously undergone diagnostic testicular biopsy. Spermatogenetic arrest was diagnosed at the round spermatid stage (n=6) or primary spermatocyte stage (n=3). A second (therapeutic) testicular biopsy was performed and round spermatid nuclei were recovered from all the participants. Results: Forty-nine mature oocytes were successfully injected with nuclei and then cultured for 72 hr. Twenty-four embryos were transferred to nine women. No pregnancy was achieved. Conclusions: Round spermatids can be recovered from therapeutic testicular biopsy material of men negative for round spermatids in previous routine diagnostic testicular biopsy specimens. Round spermatid nuclear injections may play a role in the treatment of nonobstructive azoospermia.

Effects of cotinine on sperm motility, membrane function, and fertilizing capacity in vitro.

Abstract We evaluated the effect of cotinine on sperm fertilizing capacity in vitro. Human spermatozoa were washed and re-suspended in medium containing albumin and various concentrations of cotinine (0, 100, 200, 400, or 800 ng/ml). After an 8-h incubation period, sperm motility, hypoosmotic swelling test (HOST) outcome, and the percentage of hyperactivated spermatozoa were assayed. Aliquots of spermatozoa were then processed for the zona-free hamster oocyte sperm penetration assay (SPA) or hamster ooplasmic injections. Spermatozoa exposed to concentrations of cotinine equal to 400 or 800 ng/ml demonstrated significantly smaller outcomes for all of the above with the exception of after hamster ooplasmic injections, where high cotinine concentrations did not affect sperm viability or sperm capacity to undergo decondensation and activate hamster oocytes. It appears that cotinine concentrations of 400 or 800 ng/ml exert a detrimental effect on sperm motility, membrane function, and the ability to undergo capacitation. In addition, the current findings suggest that smokers with a high seminal plasma cotinine concentration who participate in assisted reproduction programs may be treated with intracytoplasmic sperm injections (ICSI) rather than conventional in vitro fertilization (IVF) trials.

Effects of phosphodiesterase 5 inhibitors on sperm parameters and fertilizing capacity

The aim of this review study is to elucidate the effects that phosphodiesterase 5 (PDE5) inhibitors exert on spermatozoa motility, capacitation process and on their ability to fertilize the oocyte. Second messenger systems such as the cAMP/adenylate cyclase (AC) system and the cGMP/guanylate cyclase (GC) system appear to regulate sperm functions. Increased levels of intracytosolic cAMP result in an enhancement of sperm motility and viability. The stimulation of GC by low doses of nitric oxide (NO) leads to an improvement or maintenance of sperm motility, whereas higher concentrations have an adverse effect on sperm parameters. Several in vivo and in vitro studies have been carried out in order to examine whether PDE5 inhibitors affect positively or negatively sperm parameters and sperm fertilizing capacity. The results of these studies are controversial. Some of these studies demonstrate no significant effects of PDE5 inhibitors on the motility, viability, and morphology of spermatozoa collected from men that have been treated with PDE5 inhibitors. On the other hand, several studies demonstrate a positive effect of PDE5 inhibitors on sperm motility both in vivo and in vitro. In vitro studies of sildenafil citrate demonstrate a stimulatory effect on sperm motility with an increase in intracellular cAMP suggesting an inhibitory action of sildenafil citrate on a PDE isoform other than the PDE5. On the other hand, tadalafils actions appear to be associated with the inhibitory effect of this compound on PDE11. In vivo studies in men treated with vardenafil in a daily basis demonstrated a significantly larger total number of spermatozoa per ejaculate, quantitative sperm motility, and qualitative sperm motility; it has been suggested that vardenafil administration enhances the secretory function of the prostate and subsequently increases the qualitative and quantitative motility of spermatozoa. The effect that PDE5 inhibitors exert on sperm parameters may lead to the improvement of the outcome of assisted reproductive technology (ART) programs. In the future PDE5 inhibitors might serve as adjunct therapeutical agents for the alleviation of male infertility.

Expression of bcl-2, p53 oncoprotein, and proliferating cell nuclear antigen in renal cell carcinoma.

Objectives: This study was designed to examine the immunohistochemical expression of bcl-2, p53, and proliferating cell nuclear antigen (PCNA) and the relation of this expression to clinicopathological characteristics and prognosis in renal cell carcinoma (RCC). Methods: The expression of bcl-2, p53 protein, and PCNA was studied by immunohistochemical methods in paraffin-embedded nephrectomy specimens from 53 patients whose clinicopathological data had already become clear. Results: The expression of the bcl-2 protein was recognized in 34 cases (64%); the expression of the p53 protein, however, was seen in only 1 case. Bcl-2 positivity was not associated with any pathological parameters or prognosis. If the percentage of PCNA-positive cancer cells as compared to the total amount of cancer cells was defined as a labeling index (LI), a high PCNA LI number correlated significantly with a high T category, high grade, venous invasion, and shortened survival. Among the conventional pathological parameters, the T category, nuclear grade, and venous invasion had the most significant effect on prognosis. A multivariate analysis in the parameters of PCNA, T category, nuclear grade, and venous invasion demonstrated that only nuclear grade had a significant effect on prognosis. Conclusions: The inhibitory effect of the bcl-2 gene on apoptosis related to tumor development is not clear, and the expression of the p53 protein is uncommon in RCC. PCNA seems to be a good objective and quantitative marker of the biological malignant potential in RCC, although the assessment of malignant potential in combination with conventional pathological parameters is indispensable.

BLADDER DYSFUNCTION AFTER ACUTE URINARY RETENTION IN RATS

PURPOSE We investigated bladder function in acute urinary retention and subsequent catheterization in rat bladders. MATERIALS AND METHODS The penile urethra in rats was clamped with a small clip and cystostomy was performed to infuse 3 ml. of saline for inducing acute urinary retention. At 30 minutes after the induction of urinary retention the cystostomy was opened to empty the bladder. In functional studies contractile responses to carbachol were measured in group 1-before, group 2-at 3 ml. of urinary retention, group 3-at 3 ml. of urinary retention exposed for 30 minutes and group 4-30 minutes after catheterization. Moreover, in vivo real-time monitoring of blood flow and vesical pressure were measured in the bladders with a laser Doppler flowmeter and cystometrography, respectively. Malonaldehyde and 4-hydroxyalkenals were measured by colorimetric assay in these groups. RESULTS In functional studies the mean maximum contractile response value plus or minus standard deviation of carbachol-to-bladder in groups 1 to 4 was 11.8 +/- 1.3, 11.9 +/- 1.7, 9.8 +/- 0.8 and 6.9 +/- 0.7 gm./mm.2, respectively. In real-time monitoring of blood flow and vesical pressure acute urinary retention significantly decreased blood flow and increased vesical pressure, and subsequent catheterization increased blood flow and decreased vesical pressure in the bladders. The concentrations of malonaldehyde and 4-hydroxyalkenals in the bladders in group 4 were significantly higher than in the other groups. CONCLUSIONS Our data indicate that bladder dysfunction after catheterization is partially caused by free radicals, which have an important role in bladder dysfunction during acute urinary retention.

Effect of ischemia-reperfusion on contractile function of rat urinary bladder: Possible role of nitric oxide

Because there are increasing evidences that nitric oxide (NO) plays important roles in ischemia-reperfusion injury in several systems, we investigated the role of NO in ischemia-reperfusion injury of the rat urinary bladder. Rat abdominal aorta was clamped with a small clip to induce ischemia-reperfusion injury in the rat bladder dome. In functional studies, contractile responses to carbachol were cumulatively measured after the urinary bladder was treated with various duration (0, 30, 60, and 90 min) of ischemia. The injury of rat bladder functioning was dependent on ischemic periods. Significant decreases in the Emax (maximum contractile response) values were observed in the bladder subjected to 60 or 90 min ischemia. Furthermore, the subsequent 30 min reperfusion caused additional damages of the contractile response in bladder muscles. To investigate the role of NO in the ischemia (30 min)-reperfusion (30 min) injury, NG-nitro-L-arginine methylester (L-NAME) was injected intraperitoneally 30 min before the ischemia. Treatment of L-NAME (30 and 100 mg/kg) partly but significantly prevented the reduction contractile responses to carbachol of the rat bladder dome. In histological studies, the ischemia-reperfusion caused infiltration of leukocytes and rupture of microcirculation in the regions of submucosa and smooth muscle without a corresponding sloughing of mucosal cells. The histological damages were also prevented by treatment with L-NAME. Therefore, these data suggested that ischemia-reperfusion of the urinary bladder may result in dysfunction of the contractile response to autonomic nervous system and that nitric oxide may act as a cell/tissue damaging agent in ischemia-reperfusion injury.