Substance P restores spermatogenesis in busulfan-treated mice: A new strategy for male infertility therapy

m6A RNA methylation modulates autophagy by targeting Map1lc3b in bisphenol A induced Leydig cell dysfunction

Bisphenol A (BPA) exposure can affect testicular Leydig cells (LCs), potentially causing male infertility. Research suggests that RNA epigenetic response to environmental exposure may impact LCs function and testosterone production, but the role of N6-methyladenosine (m6A) RNA methylation in mediating BPA exposure and its regulatory mechanisms remain unknown. Here, we demonstrate that BPA exposure significantly reduces testosterone biosynthesis and upregulates m6A modification in LCs using both in vivo and in vitro models. The involvement of the m6A "writer" METTL3 and the "eraser" ALKBH5 in regulating LCs m6A levels during BPA exposure was discovered, highlighting their central role. Manipulating these factors to reduce m6A methylation levels demonstrated potential for alleviating BPA-induced damage to LCs. Furthermore, integrated analysis of transcriptomic and MeRIP sequencing data reveals that the upregulation of m6A levels induced by BPA specifically targets the Map1lc3b mRNA, a pivotal regulator of autophagy, thereby exerting suppressive effects on autophagic processes. In conclusion, our findings suggest that targeting m6A RNA methylation could be a potential therapeutic approach to mitigate BPA-induced reproductive toxicity, offering novel insights into the epigenetic regulation of male reproductive health.

Polydatin, a derivative of resveratrol, ameliorates busulfan-induced oligozoospermia in mice by inhibiting NF-κB pathway activation and suppressing ferroptosis

Polydatin (PD), a glucoside derivative of resveratrol (RES), is extracted as a monomer compound from the dried rhizome of Polygonum cuspidatum. Our laboratory synthesized PD via the biotransformation of resveratrol. To assess the reproductive protective effects of PD, an oligozoospermia mouse model was induced by administering 30 mg/kg busulfan (BUS) via intraperitoneal injection. Initially, mice were categorized into groups based on PD concentrations of 10, 50, and 100 mg/kg. Subsequently, the optimal concentration of 10 mg/kg was ascertained based on testis weight and spermatological parameters. Additionally, a 10 mg/kg resveratrol group was included as a control. The findings revealed that exposure to BUS resulted in a reduction of testicular weight, diminished spermatogenic cells and epididymal sperm counts, increased sperm deformity, disordered testicular cytoskeleton, compromised blood-testis barrier integrity, and a significant decrease in serum sex hormone levels, notably testosterone. This resulted in decreased expression of androgen receptors and other testosterone-related proteins, increased levels of malondialdehyde and reactive oxygen species, and promoted testicular ferroptosis. However, PD could successfully reverse these injuries. High-throughput sequencing data demonstrated that polydatin significantly downregulated the expression of inflammatory and metabolic genes, including PRKCQ and CARD11. These proteins are pivotal in the activation of the NF-κB pathway during the inflammatory response. Molecular docking studies showed that PD could interact with PRKCQ and CARD11 to reduce the level of inflammation. Additionally, PD was shown to interact with the ferroptosis-promoting gene ACSL4, modulating ferroptosis. In summary, PD facilitates the reversal of BUS-induced oligozoospermia through the mitigation of oxidative stress and inflammation, the inhibition of ferroptosis, and the modulation of hormonal levels.

Testicular weight deficits, altered variables of antioxidant defense system, spermatogenesis impairment, and inflammation induced by busulfan injection are ameliorated by gallic acid administration in rats

This study evaluated the long-term protective effect of gallic acid (GAL) against testicular lesions induced by busulfan (BUSLF) in Wistar rats. Thirty (30) male rats weighing 60-70 g were randomized into three groups of ten in each group: control (2 ml kg-1 body weight (b.w) olive oil), BUSLF (10 mg kg-1 b.w), and BUSLF + GAL (10 mg kg-1 b.w BUSLF + 20 mg kg-1 b.w GAL). BUSLF was injected (intraperitoneally) concurrently with GAL (oral gavage) on day 1 but GAL administration continues for 12 weeks in the BUSLF + GAL animals. At the end of the study, all animals did not show relevant changes in body weights, but absolute testis weight and gonado-somatic index were decreased in the BUSLF-treated animals compared to the control values (p < 0.05). These biometric data remained unchanged in the BUSLF + GAL group relative to the control but were higher than the BUSLF values (p < 0.05). GAL co-treatment counteracted BUSLF-induced decrease in glutathione peroxidase activity and an increase in hydrogen peroxide, malondialdehyde, and carbonyl protein concentrations in the testis. Changes in testicular sorbitol and lactate dehydrogenases and myeloperoxidase activities in BUSLF-treated animals were ameliorated in the BUSLF + GAL-treated animals. GAL co-treatment also prevented BUSLF-induced decrease in testosterone and sialic acid concentrations and sperm quality. The spermatogenesis score index and histological changes induced by BUSLF were also abated in the BUSLF + GAL group. GAL has been established as an effective treatment regimen for the gonadal side effects of BUSLF in a rat model.

The impact of busulfan on the testicular structure in prepubertal rats: A histological, ultrastructural and immunohistochemical study

Busulfan is a widely used cancer chemotherapeutic agent. Temporary or permanent sterility in male patients is one of the most common side effects of this drug. The present study was performed to evaluate the changes in the microscopic structure of the testes of prepubertal rats, as well as the changes in PCNA and caspase-3 immune expression, at different durations after busulfan administration. The rats were 5 weeks old and were divided into two main groups. Control group and busulfan treated group. Busulfan treated group received a single dose of busulfan (40 mg/kg), then animals were subdivided to three subgroups; IIa, IIb, IIc which were sacrificed after four, ten and twenty weeks, respectively, from the beginning of the experiment. Light and electron microscopic studies were done. Serum testosterone level and relative testes weight were assessed. Immunohistochemical staining for anti-proliferating cell nuclear antigen (PCNA) and anti-caspase-3 antigen was also done. Morphometric and statistical studies were carried out. Group II revealed histological and ultrastructural degenerative changes including congested blood vessels and degenerated spermatogenic epithelium, Sertoli cells, and Leydig cells. These changes were more evident after 10 weeks of busulfan administration and were accompanied by absence of mature sperms in the lumen of seminiferous tubules. These changes were associated with a significant reduction in relative testes weight, testosterone level, germinal epithelial height and seminiferous tubule diameter. Moreover, PCNA and caspase-3 immune expression was significantly altered in busulfan treated group. Mild improvement in testicular structure was observed 20 weeks after busulfan treatment.

Lovastatin promotes the self-renewal of murine and primate spermatogonial stem cells

The spermatogonial stem cell (SSC) niche is critical for SSC maintenance and subsequent spermatogenesis. Numerous reproductive hazards impair the SSC niche, thereby resulting in aberrant SSC self-renewal and male infertility. However, promising agents targeting the impaired SSC niche to promote SSC self-renewal are still limited. Here, we screen out and assess the effects of Lovastatin on the self-renewal of mouse SSCs (mSSCs). Mechanistically, Lovastatin promotes the self-renewal of mSSCs and inhibits its inflammation and apoptosis through the regulation of isoprenoid intermediates. Remarkably, treatment by Lovastatin could promote the proliferation of undifferentiated spermatogonia in the male gonadotoxicity model generated by busulfan injection. Of note, we demonstrate that Lovastatin could enhance the proliferation of primate undifferentiated spermatogonia. Collectively, our findings uncover that lovastatin could promote the self-renewal of both murine and primate SSCs and have implications for the treatment of certain types of male infertility using small compounds.

Carob extract induces spermatogenesis in an infertile mouse model via upregulation of Prm1, Plzf, Bcl-6b, Dazl, Ngn3, Stra8, and Smc1b

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnopharmacological studies for drug discovery from natural compounds play an important role for developing current therapeutical platforms. Plants are a group of natural sources which have been served as the basis in the treatment of many diseases for centuries. In this regard, Ceratonia siliqua (carob) is one of the herbal medicine which is traditionally used for male infertility treatments. But so far the main mechanisms for effects of carob are unknown. Here, we intend to investigate the ability of carob extract to induce spermatogenesis in an azoospermia mouse model and determine the mechanisms that underlie its function.

AIM OF THE STUDY

This is a pre-clinical animal model study to evaluate the effect of carob extract in spermatogenesis recovery.

METHODS

We established an infertile mouse model with the intent to examine the ability of carob extract as a potential herbal medicine for restoration of male fertility. Sperm parameters, as well as gene expression dynamics and levels of spermatogenesis hormones, were evaluated 35 days after carob administration.

RESULTS

Significant enhanced sperm parameters (P < 0.05) showed that the carob extract could induce spermatogenesis in the infertile mouse model. Our data suggested an anti-apototic and inducer role in the expressions of cell cycle regulating genes. Carob extract improved the spermatogenesis niche by considerable affecting Sertoli and Leydig cells (P < 0.05). The carob-treated mice were fertile and contributed to healthy offspring that matured. Our data confirmed that this extract triggered the hormonal system, the spermatogenesis-related gene expression network, and signaling pathways to induce and promote sperm production with notable level (P < 0.05). We found that the aqueous extract consisted of a polar and mainly well water-soluble substance. Carob extract might upregulate spermatogenesis hormones via its amino acid components, which were detected in the extract by liquid chromatography-mass spectrometry (LC-MS).

CONCLUSION

Our results strongly suggest that carob extract might be a promising future treatment option for male infertility. This finding could pave the way for clinical trials in infertile men. This is the first study that has provided reliable, strong pre-clinical evidence for carob extract as an effective candidate for fertility recovery in cancer-related azoospermia.

Modeling methods for busulfan-induced oligospermia and asthenozoospermia in mice: a systematic review and meta-analysis

OBJECTIVE

Modeling methods for busulfan-induced oligoasthenozoospermia are controversial. We aimed to systematically review the modeling method of busulfan-induced oligospermia and asthenozoospermia, and analyze changes in various evaluation indicators at different busulfan doses over time.

METHODS

We searched the Cochrane Library, PubMed databases, Web of Science, the Chinese National Knowledge Infrastructure, and the Chinese Biomedical Literature Service System until April 9, 2022. Animal experiments of busulfan-induced spermatogenesis dysfunction were included and screened. The model mortality and parameters of the evaluation indicators were subjected to meta-analysis.

RESULTS

Twenty-nine animal studies were included (control/model: 669/1829). The mortality of mice increased with busulfan dose. Significant spermatogenesis impairment occurred within 5 weeks, regardless of busulfan dose (10-40 mg/kg). Testicular weight (weighted mean difference [WMD]: - 0.04, 95% CI: - 0.05, - 0.03), testicular index (WMD: - 2.10, 95% CI: - 2.43, - 1.76), and Johnsen score (WMD: - 4.67, 95% CI: - 5.99, - 3.35) were significantly decreased. The pooled sperm counts of the model group were reduced by 32.8 × 106/ml (WMD: - 32.8, 95% CI: - 44.34, - 21.28), and sperm motility decreased by 37% (WMD: - 0.37, 95% CI: - 0.47, - 0.27). Sperm counts decreased slightly (WMD: - 3.03, 95% CI: - 3.42, - 2.64) in an intratesticular injection of low-dose busulfan (4 - 6 mg/kg), and the model almost returned to normal after one seminiferous cycle.

CONCLUSION

The model using low-dose busulfan (10 - 20 mg/kg) returned to normal after 10 - 15 weeks. However, in some spermatogenesis cycles, testicular weight reduction and testicular spermatogenic function damage were not proportional to busulfan dose. Sperm counts and motility results in different studies had significant heterogeneity. Standard protocols for sperm assessment in animal models were needed to reduce heterogeneity between studies.

Food-Derived High Arginine Peptides Promote Spermatogenesis Recovery in Busulfan Treated Mice

Food-derived peptides with high arginine content have important applications in medicine and food industries, but their potential application in the treatment of oligoasthenospermia remains elusive. Here, we report that high-arginine peptides, such as Oyster peptides and Perilla purple peptides were able to promote spermatogenesis recovery in busulfan-treated mice. We found that both Opp and Ppp could increase sperm concentration and motility after busulfan-induced testicular damage in mice. Further research revealed that Opp and Ppp might promote spermatogonia proliferation, which improved blood-testis barrier recovery between Sertoli cells. Taken together, these high-arginine peptides might be used as a medication or therapeutic component of a diet prescription to improve the fertility of some oligoasthenospermia patients.