Testicular Temperature Research Articles

The Diaper Dilemma: Do Plastic-Lined Diapers Impair Male Fertility?

Infertile men have long been advised to exchange their briefs for boxers in order to decrease external testicular temperature in hope of increasing

Assessment of testicular core temperatures using microwave thermography.

A new method for the reliable assessment of testicular core temperature using microwave technology is presented. This study was designed to assess whether alterations in testicular thermoregulation could be reliably demonstrated in patients with clinically apparent varicoceles (n = 36), in those with idiopathic male infertility (n = 52) and in fertile donors (n = 20) using this new microwave thermographic technique. The measurements obtained were found to be reliable and reproducible. Testicular core temperature measurements were significantly different between the groups (P < 0.001). Furthermore, there was a temperature gradient between the scrotal neck and the testicular core in all groups; testicular core temperatures were lower than scrotal neck temperatures. The magnitude of this temperature difference was also significantly different (P < 0.001) between the groups. Microwave testicular thermography is a new technique that is safe and accurate. Preliminary results suggest altered testicular thermoregulation in a group of patients with impaired spermatogenesis with and without varicocele. Testicular temperature profiles obtained by microwave thermography may be of value in the assessment of infertile men with or without a varicocele.

Arrest of spermatogenesis in mice expressing an active heat shock transcription factor 1.

In mammals, testicular temperature is lower than core body temperature, and the vulnerable nature of spermatogenesis to thermal insult has been known for a century. However, the primary target affected by increases in temperature is not yet clear. We report here that male mice expressing an active form of heat shock transcription factor 1 (HSF1) in the testis are infertile due to a block in spermatogenesis. The germ cells entered meiotic prophase and were arrested at pachytene stage, and there was a significant increase in the number of apoptotic germ cells in these mice. In wild-type mice, a single heat exposure caused the activation of HSF1 and similar histological changes such as a stage-specific apoptosis of pachytene spermatocytes. These results suggest that male infertility caused by thermal insult is at least partly due to the activation of HSF1, which induces the primary spermatocytes to undergo apoptosis.

Effects of hypercholesterolaemia on Leydig and Sertoli cell secretory function and the overall sperm fertilizing capacity in the rabbit.

The effects of hypercholesterolaemia on testicular endocrine and exocrine function were evaluated. The influence of hypercholesterolaemia on sperm quality, quantity, and fertilizing potential was also determined. Ten mature rabbits (group A) were fed chow containing 3% cholesterol for 12 weeks. Ten control rabbits (group B) were fed normal chow for the same period. At the end of the experimental period testosterone profiles and sperm parameters were evaluated and the sperm reproductive potential was assessed by in vitro fertilization (IVF) techniques. Peripheral serum testosterone responses to testicular stimulation with human chorionic gonadotrophin, androgen-binding protein activity in testicular cytosols, sperm concentration, sperm motility, length of sperm midpiece, and IVF outcome were all significantly lower in group A than in group B. In contrast, serum cholesterol concentrations were significantly higher in group A. There were no significant differences in either testicular versus intra-abdominal temperature differences or cholesterol concentrations in seminal plasma or testicular tissue between groups A and B. The results suggest that hypercholesterolaemia has a detrimental effect on Leydig and Sertoli cell secretory function, spermatogenesis, epididymal sperm maturation process, and the overall sperm fertilizing capacity.

THE EFFECTS OF MESH BIOPROSTHESIS ON THE SPERMATIC CORD STRUCTURES: A PRELIMINARY REPORT IN A CANINE MODEL

Purpose The use of mesh bioprosthesis during inguinal herniorrhaphy is now considered routine. To our knowledge, no studies have examined the effects of mesh induced fibrosis on the structure and function of the adjacent spermatic cord. We present our experience in a canine model. Materials and Methods Unilateral inguinal hernia defects were created in 12 male beagle dogs. Half were repaired using Marlex [TM] mesh and half using a classic Shouldice technique. The inguinal anatomy was then re-examined at 6 and 12 months. Testicular temperature and volume, peripheral and testicular vein testosterone levels, testicular blood flow, vasography, testicular and cord histology, and sperm motility/morphology were recorded. Groups were compared with each other as well as to the non-operated (control) side. Results Although post-operative testicular volumes from both the mesh and Shouldice groups were similar to controls (p >0.05), there was a downward trend after mesh repair (17.8 cc pre versus 12.6 cc post) but this did not reach statistical significance (p = 0.17). Testicular temperatures and blood flow did not differ between experimental groups and controls. While testicular vein testosterone levels were significantly higher than peripheral venous levels after Shouldice repair, this difference was lost after mesh repair. Contralateral (control) testicular vein testosterone levels were higher in animals repaired with mesh than by an anatomic Shouldice repair (p <0.05). There was a significant decrease in cross sectional vasal luminal diameter in both the anatomic and mesh repair groups versus their respective contralateral controls (p <0.05). This was correlated with a marked foreign body reaction to the mesh in the soft tissues surrounding the vas in spermatic cords exposed to Marlex. All vasograms demonstrated patency. Gross pathology was abnormal in 3/6 dogs with mesh repair (2 hydroceles and 1 ischemic testis) and 0/6 animals after Shouldice repair. A traumatic neuroma was identified in the mesh group. Sperm morphology and motility did not differ between the two groups. Conclusions Half of the testicles had gross abnormalities after mesh repair versus none in the control and Shouldice dogs. Although all vasograms were patent, vasal luminal size was significantly decreased with a marked soft tissue foreign body reaction identified after mesh repair. A traumatic neuroma was identified suggesting nerve entrapment in the fibrotic mesh reaction, which may account for post-operative pain seen in some patients. Marlex [TM] mesh may adversely affect spermatic cord structure and function and further work is required to fully elucidate its effects.

ARE BOXER SHORTS REALLY BETTER? A CRITICAL ANALYSIS OF THE ROLE OF UNDERWEAR TYPE IN MALE SUBFERTILITY

Purpose Elevation of testicular temperature may result in arrest of spermatogenesis, abnormal semen parameters and sterility. It has been proposed that brief style underwear may produce scrotal hyperthermia and lead to clinical subfertility. Although this idea is regarded as dogma by many in the lay community and the changing of underwear type is a therapy frequently recommended by medical practitioners, there is a paucity of data measuring scrotal temperature as a function of underwear type. Materials and Methods Scrotal, core and skin temperatures were measured in 97 consecutive men presenting for evaluation of primary clinical subfertility. These cases were categorized by underwear type to boxer or brief group. Semen analyses were obtained in all patients. Individuals from each group were compared to ascertain differences in temperature when wearing and not wearing underwear. Baseline semen parameters also were compared. In 14 subjects (crossover group) underwear type was changed to the alternative type and scrotal temperature measurements were repeated. Literature regarding underwear type, testicular temperature and/or fertility was reviewed and critically analyzed. Results Mean scrotal temperature plus or minus standard deviation was 33.8 ± 0.8C and 33.6 ± 1.1C in the boxer and brief group, respectively. There were no significant temperature differences between the groups. Differential temperatures comparing core to scrotal temperature and semen parameters also were not significantly different. These observations remained constant in the crossover group. Conclusions The hyperthermic effect of brief style underwear has been exaggerated. In our study there was no difference in scrotal temperature depending on underwear type. It is unlikely that underwear type has a significant effect on male fertility. Routinely advising infertility patients to wear boxer shorts cannot be supported by available scientific evidence.

Contractility and electrophysiological parameters of cremaster muscles of boys with a hernia or undescended testis

Background/Purpose : The cremaster muscle (CM) has been considered to participate in regulation of blood flow and temperature of the testis. Its contribution to testicular descent has been suggested. However, there is limited information about the CM in physiological and pathological states. Therefore, an experimental study has been conducted to evaluate and compare the contractile and electrophysiological properties of CM in boys with descended or undescended testes. Methods : Identical CM strips were obtained from eight boys who underwent orchidopexy with a mean age of 3 ± 2.2 years and from eight boys who underwent herniorrhaphy with a mean age of 4 ± 1.3 years. Muscle strips of 3 × 8 mm were vertically attached to an isometric force displacement transducer, and direct muscle contractions were elicited by rectangular electrical pulses. Direct isometric muscle contractions were recorded in an organ bath containing mammalian Ringer's solution. In electrophysiological experiments, conventional microelectrode techniques were used. Results : Direct electrical stimulation of CM strips obtained from patients with descended and undescended testes elicited muscle twitches and frequency-dependent contractile responses. Tetanic contractions of undescended testes at 100 Hz were 67% greater in amplitude than that of descended testes ( P < .002). Muscle strips of both groups exhibited increased twitch amplitudes by 105% ± 37% when the temperature of the bathing solution was increased from 22° to 37°C ( P < .001). The electrophysiological findings were similar. Conclusions : Contrary to other striated muscles, elevated temperature increases the contractility of CM. If the increased contractility by an increase in temperature is a property unique for CM, it should reflect the attempts at regulating testicular blood flow or temperature. The increased amplitude of contractions encountered among the CM of boys with undescended testis suggests the CM to have a role on the location of the testis.

Temperature sensitivity of primary spermatocyte DNA synthesis in immature mice confirmed by bromodeoxyuridine labelling in vitro.

To investigate the relationship between temperature and DNA synthesis of immature germ cells and to determine whether the early primary spermatocytes proliferate at a 'scrotal' temperature of 32 degrees C in vitro. Day-7 mouse testes (n = 16) were cultured with 10% fetal calf serum (FCS) for 3 days at 32 degrees C or 37 degrees C and labelled by bromodeoxyuridine (BrDU) for a further hour. The BrDU-labelled cells were detected by immunohistochemical staining using a monoclonal anti-BrDU antibody. The numbers of primary spermatocytes with BrDU-labelling or unlabelled in each tubule were determined as an index of spermatocyte DNA synthesis. In addition, the cultured media at different temperatures were collected and the testosterone levels measured by radioimmunoassay. The numbers of primary spermatocytes (P < 0.01) and the BrDU-labelling index in primary spermatocytes per tubule at 32 degrees C in vitro were significantly higher (P < 0.001) than in the culture at 37 degrees C. The testosterone levels in the culture media at 32 degrees C were also markedly higher than in the culture at 37 degrees C (P < 0.01). These observations indicate that DNA synthesis of early primary spermatocytes and testosterone production can be stimulated by lower testicular temperature, even in immature mouse testes that are naturally located in the intra-abdominal cavity.

Reduction in Testicular Temperature After Varicocelectomy in Infertile Men

Reduction in Testicular Temperature After Varicocelectomy in Infertile Men

Reduction in Testicular Temperature After Varicocelectomy in Infertile Men

Reduction in Testicular Temperature After Varicocelectomy in Infertile Men

Heat-induced germ cell deficiency in the teleosts Odontesthes bonariensis and Patagonina hatcheri.

Pathological or experimental elevation of testicular temperature is known to trigger degeneration and disappearance of germ cells in scrotal mammals. In contrast, there are no reports of heat-induced germ cell deficiency in males of non-scrotal mammals and other vertebrate taxa, nor in females of any species. This study describes the induction of germ cell deficiency up to complete sterility in the teleosts Patagonina hatcheri and Odontesthes bonariensis by rearing larvae and juveniles for prolonged periods at incipient lethal, high temperatures (27-28.5 and 29 degrees C, respectively). It was shown that female germ cells are also heat-sensitive and disappear under high temperatures. The potential implications of these findings for physiological, ecological, and environmental studies and the usefulness of heat-induced germ cell-deficient fish in research and animal production are discussed.

Reduction in testicular temperature after varicocelectomy in infertile men

Objectives To study the effects of varicocelectomy on testicular temperature. Methods Testicular skin surface temperature was directly measured with an electronic thermometer calibrated to 0.01°C in 119 men before and after microsurgical varicocelectomy and in 45 control patients without varicocele. Results Testicular temperatures in men with varicocele were elevated preoperatively (right side [R]: 34.00 ± 0.91°C/left side [L]: 34.37 ± 0.87°C unilateral; R: 34.07 ± 0.83°C/L 34.34 ± 0.85°C bilateral) relative to control patients (R: 33.04 ± 2.47°C/L 32.86 ± 2.52°C) (P <0.01). Postoperative temperatures were unchanged in the control patients. Testicular temperatures decreased after both bilateral and unilateral varicocelectomy (R: 33.03 ± 0.85°C/L 32.84 ± 1 .0°C unilateral; R: 33.27 ± 1.0°C/L 33.54 ± 1.2°C bilateral) to levels nearly identical to those of control patients (P <0.001). Conclusions Testicular temperatures were elevated bilaterally in men with both unilateral and bilateral varicoceles. Both unilateral and bilateral microsurgical varicocelectomy results in a bilateral decrease in testicular temperature. These results support the hypothesis that a defect in testicular thermoregulation contributes to the pathophysiology of varicocele and demonstrate, for the first time in humans, the efficacy of varicocelectomy in restoring normal testicular temperatures.

Effect of experimental infection with [formula omitted] and scrotal insulation on leydig cell steroidogenesis in the ram

Testicular steroid content and Leydig cell steroidogenesis in vitro were investigated in rams on Days 28 and 58 after Trypanosoma congolense infection and were compared with those of rams in which testicular temperature had been raised artificially by insulation of the scrotum for 58 d. Testicular testosterone content increased significantly on Day 28 after infection but was lower than that of controls on Day 58 while it increased in scrotal-insulated rams compared with that of controls by Day 58. Testicular progesterone was undetectable in the control and trypanosome-infected groups throughout the experiment, but it increased in the insulated rams by day 58. Basal (unstimulated) Leydig cell testosterone production in the infected rams was similar to that of control rams on Day 28 but was significantly lower on Day 58. Stimulation of Leydig cell testosterone production with hCG or 22R-hydroxycholesterol (22ROHC) significantly reduced in infected rams at both 28 and 58 d after infection as well as in scrotal-insulated rams on Day 58. It is concluded that the increase in testicular testosterone content in the infected and scrotal-insulated rams on Days 28 and 58, respectively, was induced by elevation of testicular temperature by trypanosome infection, perhaps through an effect on testicular blood flow. Reduced testosterone production by Leydig cells from infected and scrotal-insulated rams in response to hCG and 22ROHC suggests that trypanosome-induced pyrexia might be involved in reducing Leydig cell steroidogenesis and subsequent plasma testosterone levels, possibly by affecting enzymes involved in steroid biosynthesis.

Scrotal/Testicular Thermoregulation and the Effects of Increased Testicular Temperature in the Bull

Scrotal/testicular thermoregulation is a complex process controlled by numerous local mechanisms that attempt to maintain the testes at conditions ideal for spermatogenesis. This article provides a background of the anatomy and physiology of the bovine scrotum and its contents with emphasis on thermoregulation. Experiments are cited that demonstrate scrotal/testicular thermoregulation mechanisms and the effect that changes in ambient temperature have on internal testicular temperature and subsequent seminal quality.

Contribution of the scrotum, testes, and testicular artery to scrotal/testicular thermoregulation in bulls at two ambient temperatures.

The objective of this study was to determine the contribution of the scrotum, testes, and the testicular artery to scrotal/testicular thermoregulation in bulls at two ambient temperatures. Crossbred beef bulls, 1.5 years of age, were placed in controlled environment chambers at ambient temperatures of 15 degrees C (n = 5) or 25 degrees C (n = 6). The distal lateral aspects and entire ventral part of the scrotum was incised under caudal epidural anaesthesia (xylazine, 0.07 mg kg-1. Both testes were withdrawn from the scrotum and then replaced and maintained by clamping the scrotal incisions with towel clamps. One testis was randomly chosen to be the exposed testis and was withdrawn prior to temperature measurements. Surface and internal temperature were measured with infrared thermography and needle thermocouples, respectively. Temperature gradients (degree C; difference in temperature from top to bottom at 15 and at 25 degrees C) were: scrotal surface (with testis), 1.5 and 1.3; scrotal surface (without testis), 2.1 and 1.6; surface of exposed testis, -0.6 and 0.0; sub-tunic of exposed testis, -2.2 and -0.6; intratesticular (covered testis), 0.0 and 0.4; and intratesticular (exposed testis), -1.3 and 0.4. The scrotum markedly affects testicular temperature but the testes have limited influence on scrotal surface temperature. The bovine scrotum and testes have opposing temperature gradients that complement one another, resulting in a relatively uniform intratesticular temperature. These temperature gradients are attributed in part to the testicular artery, which goes from the top of the testis to the bottom, divides into several branches and ramifies dorsally and laterally before entering the testicular parenchyma. Intra-arterial temperatures (measured with needle thermocouples) were lower (P < 0.05) where the artery entered the testis than at both the bottom and top of the testis for both the covered (31.7, 33.4 and 34.3 degrees C) and exposed testis (29.6, 32.0 and 32.5 degrees C) at an ambient temperature of 15 degrees C. Temperature differences were similar, but less pronounced, at 25 degrees C (covered testis, 34.8, 36.3 and 36.5 degrees C; exposed testis, 32.4, 33.5, 33.9 degrees C). Results supported the hypothesis that blood within the testicular artery has a similar temperature at the top of the testis (just ventral to the testicular vascular cone) compared with the bottom, but subsequently cools before entering the testicular parenchyma.

The Male Menopause: Restoring Vitality and Virility

Malcolm Carruthers Thorsons, £12.99, pp 240 ISBN 0 722 53208 3 In this book Dr Malcolm Carruthers argues that many men lose energy, drive, and potency between 30 and 80 years of age after the andropause and that their symptoms can be reversed by testosterone hormone replacement therapy. He also claims a conspiracy of silence about “the male menopause” in the medical profession and sees fellow conspirators in the agrochemical industry, which floods the environment with xeno-oestrogens; in the fashion industry, which manufactures tight underwear and jeans which raise testicular temperature; and in politics, where legislators are unwilling to pay for “his as well as her HRT.” Dr Carruthers, described as a consultant andrologist with a Harley Street clinic, bases his …

The influence of temperature on changes in pH, lactate and morphology during testicular ischaemia.

To examine the role of temperature in the irreversible changes that occur within 4-6 h as ischaemic atrophy develops in the testis during testicular torsion, by determining effects on testicular pH, lactate accumulation and morphology. Tissue acidification (pH), tissue lactate and structural changes were measured at temperatures of 35, 25, 15 and 5 degrees C in 34 human testes obtained as orchidectomy specimens from patients with metastatic prostatic cancer, and in 19 testes taken from young dogs. At a normal testicular temperature of 35 degrees C, the pH decreased to 6.0 within 2 h of the onset of ischaemia; cooling to 15 degrees C extended this delay to 6 h. Tissue lactate increased from 25 mumol/g dry weight to about 200 mumol/g at 35 degrees C. Semi-thin sections of the canine testes showed swelling of the intratubular tissue with loss of interstitial space; lower temperature delayed these changes. In the present study, 6 h of torsion was relatively prolonged, in that the pH decreased to 5.8 and testicular tissue was destroyed. Acidification and histological damage can be prevented by cooling. The critical pH of the testis beyond which irreversible changes occur is unknown; a pH of < 6.0 is likely to provoke such changes.

A novel role for testicular descent; temperature-dependent induction of pertussis toxin-sensitive Gi protein function in postnatal rat Leydig cells.

The role of temperature and testicular descent in postnatal appearance of inhibitory guanine nucleotide-binding regulatory protein (G(i)) function was studied in the rat testis. Dispersed testicular cells of 5-day-old rats were incubated for 24 h at 32 or 37 C, then for another 24 h at the same temperatures in the presence and absence of pertussis toxin (PT; 100 micrograms/liter), and finally for a third 24-h period with cholera toxin (CT; 500 ng/liter) with or without PT. At both temperatures, PT treatment significantly (P < 0.05) increased the CT-stimulated cAMP output, but had no effect on basal cAMP production. When testosterone (T) production, as an indicator of Leydig cell function, was measured in the same incubation, CT-stimulated T production was greater at 32 C, but PT had no effect at either temperature. A similar finding was made when hCG (10 micrograms/liter), instead of CT, was used as the stimulus of T production. Hence, a functional G(i) protein is present in seminiferous tubules of 5-day-old testes cultured for 3 days at 32 and 37 C, but not in Leydig cells. We then examined the effects of longer exposure of 5-day-old testes to the two temperatures. After culture for 7 days with 0.1 microgram/liter ovine LH, the presence of PT at 32 C significantly (P < 0.01) enhanced CT-stimulated T production during the last 24 h of culture, but the PT effect was not observed when the culture was carried out at 37 C. Hence, G(i)-mediated modulation of Leydig cell function appears to require several days of induction at the lower temperature of 32 C. As the postnatal descent also changes the ambient testicular temperature, we next studied whether this event alters the G(i) protein function of Leydig cells. Five-day-old rats were rendered bilaterally cryptorchid or sham operated, and studied after 12 days. Testis weights did not differ between the abdominal and scrotal testes. In contrast, the basal and hCG-stimulated rates of T production were significantly (P < 0.01-0.05) higher in the scrotal testes. When dispersed cells of the scrotal and abdominal testes were incubated for 24 h at 37 C in the presence of CT with or without PT, enhancement of T production by PT was only observed in cells of the scrotal testes.(ABSTRACT TRUNCATED AT 400 WORDS)

X-Y chromosome dissociation in mice and rats exposed to increased testicular or environmental temperatures.

Heating the testes, scrota and tails of mice and rats by immersion in a water bath at 42 degrees C for 20 min caused an increased percentage of X-Y univalents in meiotic preparations made after 6 and 12 days respectively. It was also confirmed that exposing mice of a cool-adapted strain to an environment at 33 degrees C for 5 days resulted in an increase in the percentage of X-Y and autosomal univalents in meiotic preparations made after a recovery period of 2 days. Mice of a strain adapted to living at 33 degrees C also showed a higher rate of X-Y dissociation than control cool-adapted mice, but a lower frequency of autosomal univalents than cool-adapted mice exposed to the hot environment. The testes of the heat-adapted mice were even more sensitive than the testes of cool-adapted mice to the effects of local heating, as judged by the fall in testis weight 21 days afterwards.

Social, behavioural and medical factors in the aetiology of testicular cancer: results from the UK study. UK Testicular Cancer Study Group.

Although many risk factors have been proposed for the aetiology of testicular cancer, only a history of cryptorchidism is well established. All risk factors previously suggested have been explored in this study. This population-based case-control study was carried out in nine health regions in England and Wales and included 794 men, aged 15-49 years, diagnosed with a testicular germ cell tumour between 1 January 1984 and 30 September 1986, each with an individually age-matched control. Cases and controls were interviewed and data were abstracted from their general practitioner notes. Participation rates for cases and controls were 92.0% and 83.1% respectively. Where possible the mother of each interviewed man was sent a postal questionnaire for self-completion. Testicular trauma at least 2 years prior to diagnosis was associated with an odds ratio (OR) of 2.00 [95% confidence interval (CI) 1.54-2.61]. Ever having had a sexually transmitted disease was also associated with an increased risk (OR = 2.22, 95% CI 1.46-3.39). There was little evidence of an association with cigarette smoking. Sporting activity had a protective effect. Detailed exploration of testicular temperature (wearing of tight underpants, jeans or trousers, hot baths and central heating) failed to reveal any relationship with risk of testicular cancer. There were no clear occupational associations.