Abnormal spermatogenesis in mice unable to synthesize ascorbic acid

Yazama, Futoshi; Furuta, Kazuko; Fujimoto, Miwa; Sonoda, Tomoko; Shigetomi, Hiroko; Horiuchi, Toshitaka; Yamada, Manabu; Nagao, Norio; Maeda, Nobuyo

doi:10.1111/j.1447-073x.2006.00139.x

Cited by 17 publications

(7 citation statements)

References 64 publications

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“…This testicular atrophy and arrest of spermatogenesis could also be related to impaired ascorbic acid uptake as a result of low extracellular sodium concentrations. Consistent with this potential mechanism, a similar impairment of spermatogenesis has been reported in mice unable to synthesize ascorbic acid (Yazama et al 2006). Other factors may also be involved.…”

Section: Discussionsupporting

confidence: 74%

Chronic hyponatremia exacerbates multiple manifestations of senescence in male rats

Bársony

Manigrasso

et al. 2012

AGE

101

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The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is frequently responsible for chronic hyponatremia in the elderly due to age-related disruption of the inhibitory component of brain osmoregulatory mechanisms. Recent research has indicated that chronic hyponatremia is associated with gait disturbances, increased falls, and bone fragility in humans, and we have found that chronic hyponatremia causes increased bone resorption and reduced bone mineral density in young rats. In this study, we used a model of SIADH to study multi-organ consequences of chronic hyponatremia in aged rats. Sustained hyponatremia for 18 weeks caused progressive reduction of bone mineral density by DXA and decreased bone ash calcium, phosphate and sodium contents at the tibia and lumbar vertebrae. Administration of 10-fold higher vitamin D during the last 8 weeks of the study compensated for the reduction in bone formation and halted bone loss. Hyponatremic rats developed hypogonadism, as indicated by slightly lower serum testosterone and higher serum FSH and LH concentrations, markedly decreased testicular weight, and abnormal testicular histology. Aged hyponatremic rats also manifested decreased body fat, skeletal muscle sarcopenia by densitometry, and cardiomyopathy manifested as increased heart weight and perivascular and interstitial fibrosis by histology. These findings are consistent with recent results in cultured osteoclastic cells, indicating that low extracellular sodium concentrations increased oxidative stress, thereby potentially exacerbating multiple manifestations of senescence. Future prospective studies in patients with SIADH may indicate whether these multi-organ age-related comorbidities may potentially contribute to the observed increased incidence of fractures and mortality in this population.

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Section: Discussionsupporting

confidence: 74%

Chronic hyponatremia exacerbates multiple manifestations of senescence in male rats

Bársony

Manigrasso

et al. 2012

AGE

101

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“…Sperm counts in healthy men around the world have fallen by about 50 per cent in the last 50 years in the Western world (Auger et al, 1995;Kasahara et al, 2002). This may be attributed to the insufficient spermatozoa (oligozoospermia) or the lack of spermatozoa (azoospermia) (Yazama et al, 2006). Carlsen et al, (1992) reported in declining sperm concentrations in normal men .…”

Section: Infertility Oxidative Stress and Vitamin Cmentioning

confidence: 99%

Vitamin C and oxidative stress in the seminiferous epithelium

et al. 2011

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In this article, we focus on the fundamental role of vitamin C transporters for the normal delivery of vitamin C to germ cells in the adluminal compartment of seminiferous tubules. We argue that the redox status within spermatozoa or in semen is partly responsible for the etiology of infertility. In this context, antioxidant defence plays a critical role in male fertility. Vitamin C, a micronutrient required for a wide variety of metabolic functions, has long been associated with male reproduction. Two systems for vitamin C transport have been described in mammals. Facilitative hexose transporters (GLUTs), with 14 known isoforms to date, GLUT1-GLUT14, transport the oxidized form of vitamin C (dehydroascorbic acid) into the cells. Sodium ascorbic acid co-transporters (SVCTs), SVCT1 and SVCT2 transport the reduced form of vitamin C (ascorbic acid). Sertoli cells control germ cell proliferation and differentiation through cell-cell communication and form the blood-testis barrier. Because the blood-testis barrier limits direct access of molecules from the plasma into the adluminal compartment of the seminiferous tubule, one important question is the method by which germ cells obtain vitamin C. Some interesting results have thrown light on this matter. Expression of SVCT2 and some isoforms of GLUT transporters in the testis have previously been described. Our group has demonstrated that Sertoli cells express functionally active vitamin C transporters. Kinetic characteristics were described for both transport systems (SVCT and GLUT systems). Sertoli cells are able to transport both forms of vitamin C. These fi ndings are extremely relevant, because Sertoli cells may control the amount of vitamin C in the adluminal compartment, as well as regulating the availability of this metabolite throughout spermatogenesis.

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“…A unique pattern of HSP70 expression is associated with mouse spermatogenesis. Spermatocyte-specific HSP70, called HSP70-2, is expressed in pachytene spermatocytes during the meiotic phase [ 20 , 21 , 22 , 23 , 24 , 25 ]. The amino acid sequences of HSP70-2 are highly similar to those of heat-inducible HSP70s.…”

Section: Discussionmentioning

confidence: 99%

Malfunction of spermatogenesis in experimental ischemic mice

Yazama

Sato

Sonoda

2015

Journal of Reproduction and Development

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An experimental ischemia (EI)-induced mouse model was used to analyze pathological and biochemical alterations in testes. Initial morphological changes were observed in Sertoli cells of EI testes at the light microscopic level. Examination of the ultrastructure using transmission electron microscopy confirmed that Sertoli cells were partially detached from the basement membrane of the seminiferous epithelium and that the cell membranes of adjacent Sertoli cells were not joined. The functional integrity of the blood-testis barrier (BTB) was assessed using the lanthanum tracer technique. Lanthanum had penetrated into the spaces between adjacent Sertoli cells in the adluminal compartment up to the lumen of the seminiferous epithelium in EI testes. Proteome analysis showed that the expression of heat shock protein (HSP) 70 was significantly upregulated in EI testes. Western blot analysis confirmed that the expression of HSP70 increased in a time-dependent manner after the EI procedure. HSP70 immunostaining was observed in spermatocytes and in round and elongated spermatids in EI testes. Our results suggest that a change in the junctions between adjacent Sertoli cells on the basal compartment is involved in the BTB disruption in EI testes. Therefore, male infertility caused by the BTB disruption could be associated with heat stress induced by ischemia.

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Abnormal spermatogenesis in mice unable to synthesize ascorbic acid

Cited by 17 publications

References 64 publications

Chronic hyponatremia exacerbates multiple manifestations of senescence in male rats

Chronic hyponatremia exacerbates multiple manifestations of senescence in male rats

Vitamin C and oxidative stress in the seminiferous epithelium

Malfunction of spermatogenesis in experimental ischemic mice

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