Novel hydrogen-producing Si-based agent reduces oxidative stress, and improves sperm motility and in vitro fertilization rate in varicocoele

BACKGROUND

Varicocoele-induced male infertility potentially involves oxidative stress. Although varicocoelectomy is recommended for varicocoele patients presenting abnormal semen findings, no pharmacotherapeutic methods currently exist. We have recently developed a silicon-based agent that produces hydrogen by the reaction with water.

OBJECTIVES

This study aimed to investigate the therapeutic effects of oral administration of a Si-based agent on varicocoele rat.

MATERIALS AND METHODS

Twenty-one rats were divided into four groups: varicocoele + normal diet (n = 5), varicocoele + Si-based agent-supplemented diet (n = 6), sham + normal diet (n = 5), and sham + Si-based agent-supplemented diet (n = 5). All rats were euthanized four weeks after surgery.

RESULTS

The mean left epididymal sperm motility was 74.4% in the sham group, 72.3% in the sham + Si group, 57.6% in the varicocoele group, and 66.9% in the varicocoele + Si group. Epididymal sperm motility was significantly lower in the varicocoele group, but was significantly higher upon Si-based agent ingestion (P < .01). The mean left testicular weight, Johnsen's score, and left epididymal sperm concentration did not differ significantly between groups. The 8-OHdG concentration and DNA fragmentation rate were significantly increased in the varicocoele group, but were significantly decreased in the Si-based agent intake group (P < .01). Additionally, the IVF rate was significantly lower in the varicocoele group (26.3%) compared with the sham group (73.4%; P < .01), and was significantly higher in the varicocoele + Si group (51.8%) compared with the varicocoele group (P < .05), indicating that the Si-based agent improves IVF rates.

DISCUSSION AND CONCLUSION

Oral intake of the silicon-based agent improves epididymal sperm motility and in vitro fertilization rates through hydrogen production and subsequent reduction of oxidative stress. Considering the lack of effective noninvasive methods, this Si-based agent is potentially applicable for treating varicocoele-induced abnormal semen parameters.

The development of a novel antioxidant-based antiemetic drug to improve quality of life during anticancer therapy

Anticancer agents can effectively treat several types of cancers but are often limited in clinical settings due to various adverse effects. In particular, nausea and vomiting are serious side effects that markedly reduce the patients' quality of life. Accordingly, the development of novel antiemetic drugs that lack side effects is crucial, given that most conventional antiemetic drugs are known to possess side effects. In addition, reactive oxygen species generated by anticancer agents are involved in nausea and vomiting; hence, appropriate antioxidants might also be effective toward nausea and vomiting.

Silicon (Si)-based agents can abundantly generate antioxidant hydrogen in the intestine. Therefore, we assessed whether Si-based agents could be effective against nausea associated with anticancer agents in cisplatin-injected mice. We observed numerous neurons expressing c-Fos protein, a neuronal activity marker, in the nausea-associated regions of the dorsal medulla (area postrema, nuclei of the solitary tract, and dorsal vagal nuclei) 24 h after cisplatin injection. Conversely, mice fed a diet containing 2.5% Si-based agents showed a reduction in c-Fos-positive neurons.

These findings revealed that the Si-based agent alleviated cisplatin-induced nausea. Si-based agents demonstrate potent antioxidant effects by producing hydrogen, which has no known side effects and will be a safer antiemetic agent and greatly help improve the quality of life of patients undergoing anticancer drug treatment.

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Si-based agent can continuously generate a large amount of hydrogen, which has an antioxidant effect.

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Cisplatin was used at a concentration that is not nephrotoxic and induces only nausea and vomiting.

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Si-based agent alleviated nausea and vomiting associated with cisplatin administration.

Efficacy of a Si-based agent against developing renal failure in a rat remnant kidney model

Chronic renal failure is exacerbated by oxidative stress, and this condition is difficult to treat in advanced stages. Because of the lack of effective treatments, the disease is a global public health concern. We developed a Si-based agent that continuously generates hydrogen for more than 24 h by reacting with water under conditions similar to those in the gastrointestinal tract. Given the efficacy of hydrogen in the treatment of conditions associated with oxidative stress, we examined whether the Si-based agent had beneficial effects on the development of renal failure. The Si-based agent was orally administered to rats that were developing renal failure. Rats underwent 5/6 nephrectomy to establish a remnant kidney model. Specifically, on day -7, rats underwent right 2/3 nephrectomy, followed by light nephrectomy on day 0. Starting on day -3, the rats were administered a control or Si-based agent-containing diet for 8 weeks. Compared with the findings in control rats, the Si-based agent greatly suppressed the increases of both serum creatinine and urinary protein levels. All analyzed parameters of oxidative stress were significantly suppressed in the Si-based agent groups. Histopathological examination illustrated that glomerular hypertrophy was suppressed by the treatment. Quantitative real-time reverse transcription-polymerase chain reaction revealed that sirtuin 1 and heme oxygenase-1 expression was increased in the Si-based agent groups, suggesting improved antioxidant activity and reduced hypoxia. In addition, caspase-3 and interleukin-6 expression was suppressed in the Si-based agent groups, indicating the alleviation of apoptosis and inflammation. In conclusion, oral administration of a Si-based agent resulted in renoprotective effects, presumably by suppressing oxidative stress via hydrogen generation.

Neuroprotective effects of Si-based hydrogen-producing agent on 6-hydroxydopamine-induced neurotoxicity in juvenile mouse model

Neurotoxins have been extensively investigated, particularly in the field of neuroscience. They induce toxic damage, oxidative stress, and inflammation on neurons, triggering neuronal dysfunction and neurodegenerative diseases. Here we demonstrate the neuroprotective effect of a silicon (Si)-based hydrogen-producing agent (Si-based agent) in a juvenile neurotoxic mouse model induced by 6-hydroxydopamine (6-OHDA). The Si-based agent produces hydrogen in bowels and functions as an antioxidant and anti-inflammatory agent. However, the effects of the Si-based agent on neural degeneration in areas other than the lesion and behavioral alterations caused by it are largely unknown. Moreover, the neuroprotective effects of Si-based agent in the context of lactation and use during infancy have not been explored in prior studies. In this study, we show the neuroprotective effect of the Si-based agent on 6-OHDA during lactation period and infancy using the mouse model. The Si-based agent safeguards against the degradation and neuronal cell death of dopaminergic neurons and loss of dopaminergic fibers in the striatum (STR) and ventral tegmental area (VTA) caused by 6-OHDA. Furthermore, the Si-based agent exhibits a neuroprotective effect on the length of axon initial segment (AIS) in the layer 2/3 (L2/3) neurons of the medial prefrontal cortex (mPFC). As a result, the Si-based agent mitigates hyperactive behavior in a juvenile neurotoxic mouse model induced by 6-OHDA. These results suggest that the Si-based agent serves as an effective neuroprotectant and antioxidant against neurotoxic effects in the brain, offering the possibility of the Si-based agent as a neuroprotectant for nervous system diseases.

Oral administration of silicon-based agents attenuates renal fibrosis

Renal fibrosis occurs during renal failure progression and is exacerbated by oxidative stress. Oral silicon-based agents generate high intestinal hydrogen levels and reduce systemic oxidative stress. Therefore, in this study, we aimed to verify the efficacy of silicon-based agents against renal fibrosis and elucidate their underlying mechanisms in a unilateral ureteral obstruction mouse model. The mice were grouped based on the treatment provided. Comparisons between the groups were performed on postoperative days 1 and 14. On postoperative day 14, renal fibrosis, tubular cell apoptosis, and transforming growth factor-β and 4-hydroxy-2-nonenal expression were significantly reduced in the silicon-treated group (P < 0.05). Following RNA-sequencing on tissues extracted on postoperative day 14, pathway enrichment analysis was performed, revealing significant downregulation of various pathways associated with tissue fibrosis in mice in the silicon-treated group. Using tissues extracted on postoperative day 1, RNA sequencing and immunohistochemical analysis were performed. We found that complement component 3 expression was significantly reduced in mice treated with a silicon-based agent. Oxidative stress, tubular cell death, pro-fibrotic factors, and renal fibrosis were suppressed in our model following treatment with a silicon-based agent. Moreover, complement component 3 activity was inhibited during the early postoperative phase. Here, we showed that silicon-based agents represent potential novel therapeutic options against renal fibrosis.