Perturbation of epigenetic processes by doxorubicin in the mouse testis

Circulating microRNAs as promising testicular translatable safety biomarkers: current state and future perspectives

Drug-induced testicular injury (DITI) is one of the often-observed and challenging safety issues seen during drug development. Semen analysis and circulating hormones currently utilized have significant gaps in their ability to detect testicular damage accurately. In addition, no biomarkers enable a mechanistic understanding of the damage to the different regions of the testis, such as seminiferous tubules, Sertoli, and Leydig cells. MicroRNAs (miRNAs) are a class of non-coding RNAs that modulate gene expression post-transcriptionally and have been indicated to regulate a wide range of biological pathways. Circulating miRNAs can be measured in the body fluids due to tissue-specific cell injury/damage or toxicant exposure. Therefore, these circulating miRNAs have become attractive and promising non-invasive biomarkers for assessing drug-induced testicular injury, with several reports on their use as safety biomarkers for monitoring testicular damage in preclinical species. Leveraging emerging tools such as 'organs-on-chips' that can emulate the human organ's physiological environment and function is starting to enable biomarker discovery, validation, and clinical translation for regulatory qualification and implementation in drug development.

Marrubium alysson L. Ameliorated Methotrexate-Induced Testicular Damage in Mice through Regulation of Apoptosis and miRNA-29a Expression: LC-MS/MS Metabolic Profiling

Despite the efficient anti-cancer capabilities of methotrexate (MTX), it may induce myelosuppression, liver dysfunction and testicular toxicity. The purpose of this investigation was to determine whether Marrubium alysson L. (M. alysson L.) methanolic extract and its polyphenol fraction could protect mouse testicles from MTX-induced damage. We also investigated the protective effects of three selected pure flavonoid components of M. alysson L. extract. Mice were divided into seven groups (n = 8): (1) normal control, (2) MTX, (3) Methanolic extract + MTX, (4) Polyphenolic fraction + MTX, (5) Kaempferol + MTX, (6) Quercetin + MTX, and (7) Rutin + MTX. Pre-treatment of mice with the methanolic extract, the polyphenolic fraction of M. alysson L. and the selected pure compounds ameliorated the testicular histopathological damage and induced a significant increase in the serum testosterone level and testicular antioxidant enzymes along with a remarkable decline in the malondialdehyde (MDA) level versus MTX alone. Significant down-regulation of nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), p53 and miRNA-29a testicular expression was also observed in all the protected groups. Notably, the polyphenolic fraction of M. alysson L. displayed a more pronounced decline in the testicular levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and MDA, with higher testosterone levels relative to the methanolic extract. Further improvements in the Johnsen score, histopathological results and all biochemical assays were achieved by pre-treatment with the three selected pure compounds kaempferol, quercetin and rutin. In conclusion, M. alysson L. could protect against MTX-induced testicular injury by its antioxidant, anti-inflammatory, antiapoptotic activities and through the regulation of the miRNA-29a testicular expression. The present study also included chemical profiling of M. alysson L. extract, which was accomplished by LC-ESI-TOF-MS/MS analysis. Forty compounds were provisionally assigned, comprising twenty compounds discovered in the positive mode and seventeen detected in the negative mode.

Potential Gonado-Protective Effect of Cichorium endivia and Its Major Phenolic Acids against Methotrexate-Induced Testicular Injury in Mice

Cichorium endivia L. (Asteraceae) is a wide edible plant that grows in the Mediterranean region. In this study, a phytochemical investigation of C. endivia L. ethanolic extract led to the isolation of stigmasterol (1), ursolic acid (2), β-amyrin (3), azelaic acid (4), vanillic acid (5), (6S, 7E)-6-hydroxy-4,7-megastigmadien-3,9-dione (S(+)-dehydrovomifoliol) (6), 4-hydroxy phenyl acetic acid (7), vomifoliol (8), ferulic acid (9), protocatechuic acid (10), kaempferol (11), p. coumaric acid (12), and luteolin (13). In addition, the total phenolic content as well as the in vitro antioxidant activity of C. endivia L. extract were estimated. Moreover, we inspected the potential gonado-protective effect of C. endivia crude extract, its phenolic fraction, and the isolated coumaric, vanillic, and ferulic acids against methotrexate (MTX)-induced testicular injury in mice. There were seven groups: normal control, MTX control, MTX + C. endivia crude extract, MTX + C. endivia phenolic fraction, MTX + isolated coumaric acid, MTX + isolated vanillic acid, and MTX + isolated ferulic acid. MTX was given by i.p. injection of a 20 mg/kg single dose. The crude extract and phenolic fraction were given with a dose of 100 mg/kg/day, whereas the compounds were given at a dose of 10 mg/kg/day. A histopathological examination was done. The testosterone level was detected in serum together with the testicular content of malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), interleukin 1β (IL-1β), IL-6, tumor necrosis factor alpha (TNF-α), nuclear factor kappa B (NF-κB), B-cell lymphoma 2 (Bcl-2), Bcl-2 associated x protein (Bax), p53, and miR-29a. C. endivia crude extract, the phenolic fraction, and the isolated compounds showed significant elevation in their levels of testosterone, CAT, SOD, Bcl-2 with a significant decrease in their levels of MDA, TNF-α, IL-1β, IL-6, NF-κB, Bax, P53, and miR-29a compared to those of the MTX control group. In conclusion, C. endivia mitigated MTX-induced germ cell toxicity via anti-inflammatory, antioxidant, and antiapoptotic effects.

Effects of chemotherapeutic agents on male germ cells and possible ameliorating impact of antioxidants

Treatment of cancer in young adults is associated with several side effects, particularly in the reproductive system. Detrimental effects of chemotherapy on the germ cells depend on many factors including primary semen parameters, the way of drug administration, the kind and dose of chemotherapeutic regimens, and the phase of spermatogenesis during the time of drug administration. Lack of appropriate fertility preservation treatments particularly in the affected children necessitates the introduction of methods to amend the harmful effects of chemotherapeutic agents on male germ cells. Several studies have assessed the toxic effects of chemotherapeutic agents in rodent models and tested a number of antioxidants to evaluate their possible impact on the preservation of sperm cells. In the present manuscript, we describe the effects of the mostly investigated chemotherapeutic drugs in this regard i.e., cisplatin, doxorubicin, paclitaxel, 5-fluorouracil, and cyclophosphamide. As several in vivo and in vitro studies have shown the impact of antioxidants on chemotherapy-induced damage of sperms, we also describe the protective effects of antioxidants in this regard.

Ginkgo biloba Extract Attenuates Methotrexate-Induced Testicular Injury in Rats: Cross-talk Between Oxidative Stress, Inflammation, Apoptosis, and miRNA-29a Expression

Ginkgo biloba leaf extract (GIN) is a popular Chinese herbal medicine. It has a nephroprotective effect against the nephrotoxicity induced by the chemotherapeutic agent methotrexate (MTX). This work was designed to explore the testicular protective role of GIN on MTX-induced testicular injury in a rat model. The experimental protocol lasted for 10 days for the 4 studied groups. First group: received saline (normal control, NC group). The second group was administered GIN (100 mg/kg/day) orally for 10 days (GIN C). Third group: injected with MTX (20 mg/kg ip) only on the fifth day (MTX group). Fourth group: administered GIN for 10 days with MTX injection on the fifth day (GIN+MTX group). MTX induced testicular injury as evident by a marked rise in the malondialdehyde (MDA) content, interleukin-6 (IL-6) and IL-1β protein levels, nuclear factor kappa-B (NF-κB) protein expression, bcl-2 associated × protein (Bax) mRNA expression, p53 mRNA and protein expressions, and miRNA29-a expression along with a marked decline in the serum level of testosterone and superoxide dismutase (SOD) content in testicular tissue in relation to the NC group. Moreover, histopathological testicular damage with a notable decrease in the Johnsen score together with a significant elevation in the testicular injury score was observed in the MTX group in comparison to the NC group. The administration of GIN ameliorated the biochemical changes as well as the testicular histopathological findings and scores. GIN could protect against MTX-induced gonadotoxicity by its antioxidant, anti-inflammatory, antiapoptotic activities plus the regulation of the miRNA-29a testicular expression.

Three-dimensional testicular organoids as novel in vitro models of testicular biology and toxicology

Organoids are three dimensional structures consisting of multiple cell types that recapitulate the cellular architecture and functionality of native organs. Over the last decade, the advent of organoid research has opened up many avenues for basic and translational studies. Following suit of other disciplines, research groups working in the field of male reproductive biology have started establishing and characterizing testicular organoids. The three-dimensional architectural and functional similarities of organoids to their tissue of origin facilitate study of complex cell interactions, tissue development and establishment of representative, scalable models for drug and toxicity screening. In this review, we discuss the current state of testicular organoid research, their advantages over conventional monolayer culture and their potential applications in the field of reproductive biology and toxicology.

Perturbation of microRNA signalling by doxorubicin in spermatogonial, Leydig and Sertoli cell lines in vitro

We have previously shown that in addition to its widely recognised cardiotoxicity, the chemotherapeutic doxorubicin (DOX) is able to induce transcriptional, microRNA (miRNA) and DNA methylation changes in the mouse testis. These changes perturb pathways involved in stress/cell death and survival and testicular function and lead to germ cell loss and reproductive organ damage. Here, we further investigated the differential miRNA expression induced by DOX in mouse spermatogonial (GC1), Leydig (TM3) and Sertoli (TM4) cell lines in vitro. We began by performing cell cycle analysis of the three mouse testicular cell lines to evaluate their sensitivity to DOX and thus select suitable doses for miRNA profiling. In keeping with our in vivo data, the spermatogonial cell line was the most sensitive, and the Sertoli cell line the most resistant to DOX-induced cell cycle arrest. We then further demonstrated that each cell line has a distinct miRNA profile, which is perturbed upon treatment with DOX. Pathway analysis identified changes in the miRNA-mediated regulation of specialised signalling at germ-Sertoli and Sertoli-Sertoli cell junctions following treatment with DOX. Amongst the most significant disease categories associated with DOX-induced miRNA expression were organismal injury and abnormalities, and reproductive system disease. This suggests that miRNAs play significant roles in both normal testicular function and DOX-induced testicular toxicity. Comparison of our in vitro and in vivo data highlights that in vitro cell models can provide valuable mechanistic information, which may also help facilitate the development of biomarkers of testicular toxicity and high-throughput in vitro screening methods to identify potential testicular toxicants.