The protective effect of regucalcin against radiation-induced damage in testicular cells

Lycopene protects against ionizing radiation-induced testicular damage by inhibition of apoptosis and mitochondrial dysfunction

Ionizing radiation (IR) is one of the key contributors that cause male infertility by disturbing spermatogenesis. Lycopene, a carotenoid with strong antioxidant properties, was shown to protect against oxidative damage induced by IR in several experimental models. The present study was designed to explore the possible protective effects of lycopene against IR-induced testicular damage in C57BL/6 mice. Mice were administered lycopene (20 mg/kg) by oral gavage for seven consecutive days prior to a single dose of whole-body X-ray irradiation (4 Gy, 1 Gy/min). We observed that lycopene remarkably augmented sperm motility and reduced sperm abnormalities in mice following IR exposure. Histopathological analyses also revealed that lycopene ameliorated the structural damage of seminiferous tubules and enhanced the regeneration of seminiferous epithelium following IR stress. Moreover, lycopene attenuated IR-induced oxidative stress, as evidenced by a decreasing lipid peroxidation level and an increase in the antioxidant enzyme superoxide dismutase activity. In addition, lycopene reduced the γH2AX expression and the number of TUNEL-positive cells in the germinal epithelium, as well as restoring the imbalance of Bax/Bcl-2 expression induced by IR exposure. Furthermore, lycopene prevented mitochondrial membrane potential depolarization and ATP reduction and preserved the activities of mitochondrial complexes I-IV in the testes of mice after exposure to IR. Lycopene also improved mitochondrial biogenesis in testes of mice exposed to IR, presenting as restored expressions of PGC-1α, Nrf1, and Tfam. Taken together, our results suggest that lycopene alleviates IR-induced testicular damage, and the underlying mechanism involves at least in part the inhibition of the mitochondrial apoptotic pathway and the maintenance of mitochondrial respiration and biogenesis. The beneficial effect of lycopene highlights the therapeutic potential of this plant-derived antioxidant against impaired spermatogenesis and male infertility induced by IR.

Metformin Ameliorates 2.856 GHz Microwave- Radiation-Induced Reproductive Impairments in Male Rats via Inhibition of Oxidative Stress and Apoptosis

The reproductive system has been increasingly implicated as a sensitive target of microwave radiation. Oxidative stress plays a critical role in microwave radiation -induced reproductive damage, though precise mechanisms are obscure. Metformin, a widely used antidiabetic drug, has emerged as an efficient antioxidant against a variety of oxidative injuries. In the present study, we hypothesized that metformin can function as an antioxidant and protect the reproductive system from microwave radiation. To test this hypothesis, rats were exposed to 2.856 GHz microwave radiation for 6 weeks to simulate real-life exposure to high-frequency microwave radiation. Our results showed that exposure to 2.856 GHz microwave radiation elicited serum hormone disorder, decreased sperm motility, and depleted sperm energy, and it induced abnormalities of testicular structure as well as mitochondrial impairment. Metformin was found to effectively protect the reproductive system against structural and functional impairments caused by microwave radiation. In particular, metformin can ameliorate microwave-radiation-induced oxidative injury and mitigate apoptosis in the testis, as determined by glutathione/-oxidized glutathione (GSH/GSSG), lipid peroxidation, and protein expression of heme oxygenase-1 (HO-1). These findings demonstrated that exposure to 2.856 GHz microwave radiation induces obvious structural and functional impairments of the male reproductive system, and suggested that metformin can function as a promising antioxidant to inhibit microwave-radiation-induced harmful effects by inhibiting oxidative stress and apoptosis.

Losartan Attenuates Radiation-Induced Damage on Testes and Accelerates Tubular Regeneration

Male germ cells are particularly susceptible to radiation; infertility being a common consequence after radiotherapy as it impairs spermatogenesis. This study aimed to test whether treatment with losartan (LOS), a selective antagonist of angiotensin II receptor subtype 1 (AT1R), can prevent or attenuate the acute and long-term radiation-induced damage to testes. Wistar rats were randomly distributed into six groups, three of which were studied on day 2 after irradiation: control (CTRL 2), irradiated non-treated (IR 2), and irradiated and treated with LOS (IRLOS 2); and three other groups that were studied on day 60 after irradiation: control (CTRL 60), irradiated non-treated (IR 60), and irradiated and treated with LOS (IRLOS 60). Seven consecutive days before and on the day of irradiation with 2.5 Gy directly administered in the scrotum, the animals were treated with LOS (34 mg/kg/two times/day). This treatment was continued 2 or 60 days after irradiation. The sperm quality was assessed from epididymis cauda. In addition, the testes were submitted to histopathological and morphometric-stereological analysis as well as the proliferating cell nuclear antigen (PCNA) quantification. Serum FSH and LH and plasma testosterone levels were also determined. The data obtained 2 days after the irradiation showed germ cell apoptosis, formation of vacuoles in the seminiferous epithelium, sloughing of germ cells into the lumen, and retention and phagocytosis of step-19 spermatids in Sertoli basal cytoplasm. The treatment with LOS in this period did not prevent or attenuate a radio-induced damage to the testes, illustrating that this drug does not protect against apoptosis derived from direct effects of radiation. On the other hand, 60 days after exposure, the data evidenced the deleterious effects of ionizing radiation on the testes as decreasing of testicular, epididymal, and seminal vesicle masses; tubular atrophy; reduction of cellular proliferation; and loss of germ cells. LOS was able to prevent some of those deleterious effects, promoting improvements in seminal vesicle mass, sperm vitality, plasma testosterone levels, vacuole number, and cell proliferation. In conclusion, inhibition of the AngII/AT1R axis by LOS is effective in protecting the indirect/delayed radiation damage resulting from oxidative stress established in the tissue.

"Radio-Protective Effect of Aminocaproic Acid in Human Spermatozoa"

BACKGROUND

The negative effects of ionizing radiation on organs and the reproductive system are well known and documented. Exposure to gamma radiation can lead to oligospermia, azoospermia and DNA damage. Up to date, there is no effective pharmaceutical compound for protecting the male reproductive system and sperm.

OBJECTIVE

This study aimed at investigating the ability of Ɛ-aminocaproic acid (EACA) to prevent the damage of human spermatozoa and DNA induced by ionizing radiation.

MATERIALS AND METHODS

Sperm samples were obtained from healthy volunteers (35 men; 31.50 ± 7.34 years old). There were 4 experimental groups: 1) control group (CG), 2) group exposed to maximal radiation dose 67.88 mGy (RMAX), 3) low-dose radiation (minimal) 22.62 mGy (RMIN), and 4) group treated with radiation (67.88 mGy) and EACA (dose 50 ng/ml). Sperm motility, viability, and DNA damage were assessed.

RESULTS

We observed a significant decrease in total sperm motility of the RMAX group compared to CG (p < 0.05). Sperm viability in the RMAX group was also reduced in comparison to the control (p < 0.05). A significant increase in DNA fragmentation was detected in the RMAX group. The results demonstrated that the treatment of sperm with EACA led to a decrease in the fragmentation of the sperm DNA (compared to the RMAX group) (p < 0.05).

CONCLUSION

The results indicate that EACA effectively protects human spermatozoa from DNA damage induced by ionizing radiation. Treatment of spermatozoa with EACA led to the preservation of cell motility, viability, and DNA integrity upon radiation exposure.

Circadian effects of ionizing radiation on reproductive function and clock genes expression in male mouse

BACKGROUND

Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far.

METHODS

Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-β, or Ror-γ.

RESULTS

Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-β, or Ror-γ) in testis, with alteration in the rhythm parameters.

CONCLUSION

These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.

Overexpression of regucalcin mitigates the ageing-related changes in oxidative stress and sperm quality

Age-related changes, namely the increase in oxidative stress (OS) with the consequent sperm damage, result in decreased male fertility. Regucalcin (RGN) is a Ca²⁺-binding protein that has been shown to have beneficial effects on spermatogenesis by suppressing OS and chemical/radiation-induced damage. This work aims to evaluate whether RGN overexpression reduces the ageing-associated decline of male reproductive function. Sperm and testicular function analysis were performed in young-adult and senescent transgenic rats overexpressing RGN (Tg-RGN) comparatively with their wild-type (Wt) littermates. The gonadosomatic index (GI), tubular differentiation index and the expression levels of RGN and other proliferation regulators were evaluated. Moreover, the sperm parameters, OS analysis and immunolocalization of RGN were assessed, as well as morphometric evaluation of epididymal tubules. Both GI and sperm counts were reduced in the senescent Wt rats, but maintained in the Tg-RGN. Also, the levels of stem cell factor (SCF), c-Kit, and Akt were maintained in the testis of aged Tg-RGN rats, suggesting that the normal spermatogenic output was preserved over time in these animals, an effect not observed in Wt. Senescent Tg-RGN rats also presented lower sperm lipid peroxidation and total oxidant status relative to the Wt. Furthermore, aged Tg-RGN rats displayed higher sperm viability, higher frequency of sperm with normal morphology, and reduced incidence of head and neck/midpiece defects when compared with Wt, which may be a consequence of the lower OS levels found in the sperm of these animals. Interestingly, RGN expression increased with ageing in sperm, being mainly localized in the acrosome. Altogether, these findings indicate that the modulation of RGN levels may alleviate the age-related decline in sperm quality and testicular function.

The involvement of a regucalcin in suppressing hemocyte apoptosis in Pacific oyster Crassostrea gigas

Regucalcin (RGN), also known as senescence marker protein-30 (SMP30), plays a vital role in the regulation of Ca²⁺ homeostasis. In the present study, a regucalcin (designated as CgRGN) was identified from Pacific oyster Crassostrea gigas. The complete cDNA sequence of CgRGN was of 1059 bp, containing an open reading frame of 933 bp which encoded a protein of 310 amino acids. The deduced amino acid sequence of CgRGN shared similarity with other RGNs from the genome of C. gigas as well as other species. The mRNA transcripts of CgRGN were universally detected in all tested tissues, with higher level in hepatopancreas, labial palp, and gills. The relative expression level of CgRGN in hemocytes was significantly up-regulated (p < 0.05) at 3, 12, 72, and 96 h after the stimulation of lipopolysaccharide (LPS). After CgRGN expression was interfered by specific CgRGN-dsRNA, the hemocytes apoptosis rate increased dramatically at 12 h post LPS stimulation (1.56 fold, p < 0.01), compared to the control group. The caspase-3 activity in hemocytes and NO concentration in hemolymph increased significantly (p < 0.05) in dsCgRGN injection oysters. These results collectively indicated that CgRGN could suppress LPS-induced apoptosis and be involved in the immune response of oysters.

Analysis of Long Noncoding RNA and mRNA Expression Profiles of Testes with High and Low Sperm Motility in Domestic Pigeons (Columba livia)

Sperm motility is one of the most important indicators in assessing semen quality, and it is used to evaluate poultry fertility. Many long noncoding RNAs (lncRNAs) and mRNAs are involved in regulating testis development and spermatogenesis. In this study, we employed RNA sequencing to analyse the testis transcriptome (lncRNA and mRNA) of ten pigeons with high and low sperm motility. In total, 46,117 mRNAs and 17,463 lncRNAs were identified, of which 2673 mRNAs and 229 lncRNAs (P < 0.05) were significantly differentially expressed (DE) between the high and low sperm motility groups. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation analysis showed that target genes of DE lncRNAs and DE mRNAs were related to calcium ion binding, ATP binding, and spermatogenesis. Moreover, we found that UBB, a target gene of lncRNA MSTRG.7787.5, was involved in germ cell development. Our study provided a catalogue of lncRNAs and mRNAs associated with sperm motility, and they deserve further study to deepen the understanding of biological processes in the pigeon testis.

The effectiveness of traditional Japanese medicine Goshajinkigan in irradiation-induced aspermatogenesis in mice

Background

Infertility and gonadal dysfunction are well known side-effects by cancer treatment in males. In particularly, chemotherapy and radiotherapy induced testicular damage, resulting in prolonged azoospermia. However, information regarding therapeutics to treat spermatogenesis disturbance after cancer treatment is scarce. Recently, we demonstrated that Goshajinkigan, a traditional Japanese medicine, can completely rescue severe busulfan-induced aspermatogenesis in mice. In this study, we aimed to detect the effects of Goshajinkigan on aspermatogenesis after irradiation.

Methods

This is animal research about the effects of traditional Japanese medicine on infertility after cancer treatment. C57BL/6 J male mice received total body irradiation (TBI: a single dose of 6Gy) at 4 weeks of age and after 60 days were reared a Goshajinkigan (TJ107)-containing or TJ107-free control diet from day 60 to day 120. Then, two untreated females were mated with a single male from each experimental group. On day 60, 120 and 150, respectively, the sets of testes and epididymis of the mice in each group after deep anesthetization were removed for histological and cytological examinations.

Results

Histological and histopathological data showed that 6Gy TBI treatment decreased the fertility rate (4/10) in the control diet group; in contrast, in the TJ107-diet group, the fertility rate was 10/10 (p < 0.05 vs. 6Gy group). Supplementation with TJ107 was found to rescue the disrupted inter-Sertoli tight junctions via the normalization of claudin11, occludin, and ZO-1 expression and reduce serum anti-germ cell autoantibodies.

Conclusions

These findings show the therapeutic effect on TBI-induced aspermatogenesis and the recovering disrupted gonadal functions by supplementation with TJ107.

Pelvic Radiation-Induced Testicular Damage: An Experimental Study at 1 Gray

Therapeutic radiation of the pelvic region has been shown to cause damage to testicular germ cells. In this study we aimed to evaluate the effects of a low therapeutic dose of 1 Gy on the induction of cellular and histological damage in early-stage testicular germ cells and the impact of this radiation on offspring sex ratio. Unirradiated and irradiated male rats were mated with unirradiated female rats. Female rats were followed and the sex of the offspring was determined. The male rats were sacrificed at the end of the second week, and the testicular germ cells were subjected to genetic analysis along with cytological and histopathological examination. Sperm DNA was amplified with primers specific to testis-specific Y-linked protein, rat actin beta and testis-specific X-linked genes. The resulting products were separated by capillary electrophoresis. Histopathological changes were investigated by light microscopy along with the TUNEL assay and immunohistochemical staining for caspase-3. There was no significant difference between the two groups for sex ratio and size of offspring. The number of sperm cells bearing X or Y chromosomes' did not differ significantly between these two groups. However, a 1 Gy dose of radiation caused significant cytopathological and histopathological changes in the testicular tissue. In the irradiated group, edematous regions were evident. The number of caspase-3 positive cells in the germinal epithelium of the seminiferous tubules was also significantly higher in the irradiated group. Our results showed that low-dose radiation induced apoptosis and caused significant cyto- and histopathological changes in the testicular tissue. Further research is required to fully elucidate their contribution to apoptosis and if low-dose radiation may potentially lead to long-term effects in the offspring. These results may also lead us to develop a new technique using the caspase-3 staining to monitor the susceptibility to low dose radiation.

Effects of 220 MHz Pulsed Modulated Radiofrequency Field on the Sperm Quality in Rats

Under some occupational conditions, workers are inevitably exposed to high-intensity radiofrequency (RF) fields. In this study, we investigated the effects of one-month exposure to a 220 MHz pulsed modulated RF field at the power density of 50 W/m² on the sperm quality in male adult rats. The sperm quality was evaluated by measuring the number, abnormality and survival rate of sperm cells. The morphology of testis was examined by hematoxylin-eosin (HE) staining. The levels of secreting factors by Sertoli cells (SCs) and Leydig cells (LCs) were determined by enzyme linked immunosorbent assay (ELISA). The level of cleaved caspase 3 in the testis was detected by immunofluorescence staining. Finally, the expression levels of the apoptosis-related protein (caspase 3, BAX and BCL2) in the testis were assessed by Western blotting. Compared with the sham group, the sperm quality in the RF group decreased significantly. The levels of secreting factors of SCs and the morphology of the testis showed an obvious change after RF exposure. The level of the secreting factor of LCs decreased significantly after RF exposure. The levels of cleaved caspase 3, caspase 3, and the BAX/BCL2 ratio in the testis increased markedly after RF exposure. These data collectively suggested that under the present experimental conditions, 220 MHz pulsed modulated RF exposure could impair sperm quality in rats, and the disruption of the secreting function of LCs and increased apoptosis of testis cells induced by the RF field might be accounted for by this damaging effect.

Effects of Chemotherapy and Radiotherapy on Spermatogenesis: The Role of Testicular Immunology

Substantial improvements in cancer treatment have resulted in longer survival and increased quality of life in cancer survivors with minimized long-term toxicity. However, infertility and gonadal dysfunction continue to be recognized as adverse effects of anticancer therapy. In particular, alkylating agents and irradiation induce testicular damage that results in prolonged azoospermia. Although damage to and recovery of spermatogenesis after cancer treatment have been extensively studied, there is little information regarding the role of differences in testicular immunology in cancer treatment-induced male infertility. In this review, we briefly summarize available rodent and human data on immunological differences in chemotherapy or radiotherapy.

Glucose and glutamine handling in the Sertoli cells of transgenic rats overexpressing regucalcin: plasticity towards lactate production

Sertoli cells (SCs) possess the unparalleled ability to provide the germ line with growth factors and nutrients. Although SCs can oxidize amino acids, e.g., glutamine, they mostly metabolize glucose, producing high amounts of lactate, the germ cells preferential substrate. Regucalcin (RGN) is a calcium-binding protein that has been indicated as a regulator of cell metabolism. In this study, we investigated glucose and glutamine handling in the SCs of transgenic rats overexpressing RGN (Tg-RGN) comparatively with wild-type (Wt) littermates. Primary SCs isolated from adult Tg-RGN animals and maintained in culture for 24 hours, produced and exported more lactate, despite consuming less glucose. These observations were underpinned by increased expression of alanine transaminase, and augmented glutamine consumption, suggesting that alternative routes are contributing to the enhanced lactate production in the SCs of Tg-RGN rats. Moreover, lactate seems to be used by germ cells, with diminished apoptosis being detected in the seminiferous tubules of Tg-RGN animals cultured ex vivo. The obtained results showed a distinct metabolism in the SCs of Wt and Tg-RGN rats widening the roles assigned to RGN in spermatogenesis. These findings also highlighted the plasticity of SCs metabolism, a feature that would be exploited in the context of male infertility.

Comparative Profiling of MicroRNAs Reveals the Underlying Toxicological Mechanism in Mice Testis Following Carbon Ion Radiation

This study investigated the toxicity of heavy ion radiation to mice testis by microRNA (miRNA) sequencing and bioinformatics analyses. Testicular indices and histology were measured following enterocoelia irradiation with a 2 Gy carbon ion beam, with the testes exhibiting the most serious injuries at 4 weeks after carbon ion radiation (CIR) exposure. Illumina sequencing technology was used to sequence small RNA libraries of the control and irradiated groups at 4 weeks after CIR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses implicated differential miRNAs in the regulation of target genes involved in metabolism, development, and reproduction. Here, 8 miRNAs, including miR-34c-5p, miR-138, and 6 let-7 miRNA family members previously reported in testis after radiation, were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) to validate miRNA sequencing data. The differentially expressed miRNAs described here provided a novel perspective for the role of miRNAs in testis toxicity following CIR.