Next-generation sequencing-based microRNA profiling of mice testis subjected to transient heat stress

Effect of Temperature on the Development of Stages of Spermatogenesis and the Functionality of Sertoli Cells In Vitro

Spermatogenesis is the process of proliferation and differentiation of spermatogonial cells to meiotic and post-meiotic stages and sperm generation. Normal spermatogenesis occurs in vivo at 34 °C to 35 °C, and high temperatures are known to cause male infertility. The aim of the present study was to examine the effect of temperature (35 °C compared to 37 °C) on the viability/apoptosis of developed cells, on the development of different stages of spermatogenesis in 3D in vitro culture conditions, and the functionality of Sertoli cells under these conditions. We used isolated cells from seminiferous tubules of sexually immature mice. The cells were cultured in methylcellulose (as a three-dimensional (3D) in vitro culture system) and incubated in a CO2 incubator at 35 °C or 37 °C. After two to six weeks, the developed cells and organoids were collected and examined for cell viability and apoptosis markers. The development of different stages of spermatogenesis was evaluated by immunofluorescence staining or qPCR analysis using specific antibodies or primers, respectively, for cells at each stage. Factors that indicate the functionality of Sertoli cells were assessed by qPCR analysis. The developed organoids were examined by a confocal microscope. Our results show that the percentages and/or the expression levels of the developed pre-meiotic, meiotic, and post-meiotic cells were significantly higher at 35 °C compared to those at 37 °C, including the expression levels of the androgen receptor, the FSH receptor, transferrin, the androgen-binding protein (ABP), and the glial-derived nerve growth factor (GDNF) which were similarly significantly higher at 35 °C than at 37 °C. The percentages of apoptotic cells (according to acridine orange staining) and the expression levels of BAX, FAS, and CASPAS 3 were significantly higher in cultures incubated at 37 °C compared to those incubated at 35 °C. These findings support the in vivo results regarding the negative effect of high temperatures on the process of spermatogenesis and suggest a possible effect of high temperatures on the viability/apoptosis of spermatogenic cells. In addition, increasing the temperature in vitro also impaired the functionality of Sertoli cells. These findings may deepen our understanding of the mechanisms behind optimal conditions for normal spermatogenesis in vivo and in vitro.

PS-MPs or their co-exposure with cadmium impair male reproductive function through the miR-199a-5p/HIF-1α-mediated ferroptosis pathway

Microplastics (MPs) and cadmium (Cd) exist extensively in ambient environments and probably influence negatively on human health. However, the potential reproductive toxicity of MPs or MPs + Cd remains unknown. This study was aimed to observe the reproductive changes of male mice treated orally for 35 days with PS-MPs (100 mg/kg), CdCl2 (5 mg/kg) and PS-MPs plus CdCl2 mixture. We found that subchronic exposure to PS-MPs damaged mouse testicular tissue structure, reduced sperm quality and testosterone levels. Moreover, the reproductive toxicity in 0.1 μm group was stronger than 1 μm group, and mixture group was more severe than single particle size ones. Meanwhile, co-exposure of PS-MPs and Cd exacerbated reproductive injury in male mice, with an ascending toxicity of Cd, 1 μm + Cd, 0.1 μm + Cd, and 0.1+1 μm + Cd. In addition, we discovered that the testicular damage induced by PS-MPs or PS-MPs + Cd was associated with interfering the miR-199a-5p/HIF-1α/ferroptosis pathway. Promisingly, these findings will shed new light on how PS-MPs and PS-MPs + Cd damage male reproductive function.

The role of miR-199a-3p in inhibiting the proliferation of spermatogonial stem cells under heat stress

MicroRNAs (miRNAs) play a crucial role in regulating various physiological processes, including cell differentiation, proliferation, and apoptosis. However, their specific functions in response to heat stress are not fully understood. This study aimed to investigate the regulatory effects of miR-199a-3p on the proliferation of heat stress-treated spermatogonial stem cells (SSCs). SSCs were isolated from mouse testes and cultured in vitro to identify marker molecules. Lentiviruses carrying miR-199a-3p-over, miR-199a-3p-inhibit, and ID4-over constructs were generated for stable transfection. Luciferase assay was employed to confirm the targeting relationship between miR-199a-3p and ID4. An in vitro SSCs heat stress model was established, and the miR-199a-3p-inhibit and ID4-over groups were included. Cellular proliferation was assessed using CCK-8, EdU, and cell cycle analysis methods after heat stress. Expression levels of miR-199a-3p and ID4 were evaluated by western blotting and qRT-PCR. The results demonstrated that miR-199a-3p-over inhibited SSCs proliferation, while ID4-over promoted an increase in SSCs number. Luciferase assay confirmed the regulatory effect of miR-199a-3p on ID4 expression. Moreover, after heat stress treatment, miR-199a-3p-inhibit and ID4-over enhanced SSCs proliferation compared to the control group. These findings suggest that miR-199a-3p modulates SSCs proliferation by targeting ID4, especially under heat stress conditions.

Potential Function of Testicular MicroRNAs in Heat-Stress-Induced Spermatogenesis Disorders

Spermatogenesis is temperature-dependent, and the increase in testicular temperature seriously affects mammalian spermatogenesis and semen quality. In this study, the testicular heat stress model of mice was made with a 43 °C water bath for 25 min, and the effects of heat stress on semen quality and spermatogenesis-related regulators were analyzed. On the 7th day after heat stress, testis weight shrank to 68.45% and sperm density dropped to 33.20%. High-throughput sequencing analysis showed that 98 microRNAs (miRNAs) and 369 mRNAs were down-regulated, while 77 miRNAs and 1424 mRNAs were up-regulated after heat stress. Through gene ontology (GO) analysis of differentially expressed genes and miRNA-mRNA co-expression networks, it was found that heat stress may be involved in the regulation of testicular atrophy and spermatogenesis disorders by affecting cell meiosis process and cell cycle. In addition, through functional enrichment analysis, co-expression regulatory network, correlation analysis and in vitro experiment, it was found that miR-143-3p may be a representative potential key regulatory factor affecting spermatogenesis under heat stress. In summary, our results enrich the understanding of miRNAs in testicular heat stress and provide a reference for the prevention and treatment of heat-stress-induced spermatogenesis disorders.

Small RNA-seq and hormones in the testes of dwarf hamsters (Cricetulus barabensis) reveal the potential pathways in photoperiod regulated reproduction

Photoperiod regulates the functions and development of gonadal organs of seasonally breeding animals, resulting in breeding peaks in specific seasons. miRNA plays an important role in the regulation of testicular physiological functions. However, the relationship between photoperiods and miRNA levels in testes has yet to be conclusively determined. We investigated testicular miRNA of striped dwarf hamster (Cricetulus barabensis) responses to different photoperiods (long daylength [LD], moderate daylength [MD], and short daylength [SD]) and the potential pathways involved in photoperiod regulated reproduction. Testicular weights and reproductive hormone levels were measured in each of photoperiod treatments after 30 days. The concentrations of testosterone (T) and dihydrogen testosterone (DHT) in testes and Gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in serum were higher in MD than in the other two groups. Testicular weights were heaviest in MD. Small RNA-seq was performed for the testes of hamsters in three groups. A total of 769 miRNAs were identified, of which 83 were differentially expressed between LD, MD, and SD. GO and KEGG analysis of target genes revealed that some miRNAs influence testicular activities by regulating the pathways related to cell apoptosis and metabolism. Gene expression pattern analysis showed that the MAPK signaling pathway may be the core pathway for photoperiodic regulation of reproduction. These results suggest that moderate daylength is more suitable for hamster reproduction while long daylength and short daylength may regulate reproduction through different molecular pathways.

Testicular heat stress, a historical perspective and two postulates for why male germ cells are heat sensitive

Herein, we compare the different experimental regimes used to induce testicular heat stress and summarise their impact on sperm production and male fertility. Irrespective of the protocol used, scrotal heat stress causes loss of sperm production. This is first seen 1-2 weeks post heat stress, peaking 4-5 weeks thereafter. The higher the temperature, or the longer the duration of heat, the more pronounced germ cell loss becomes, within extreme cases this leads to azoospermia. The second, and often underappreciated impact of testicular hyperthermia is the production of poor-quality spermatozoa. Typically, those cells that survive hyperthermia develop into morphologically abnormal and poorly motile spermatozoa. While both apoptotic and non-apoptotic pathways are known to contribute to hyperthermic germ cell loss, the mechanisms leading to formation of poor-quality sperm remain unclear. Mechanistically, it is unlikely that testicular hyperthermia affects messenger RNA (mRNA) abundance, as a comparison of four different mammalian studies shows no consistent single gene changes. Using available evidence, we propose two novel models to explain how testicular hyperthermia impairs sperm formation. Our first model suggests aberrant alternative splicing, while the second model proposes a loss of RNA repression. Importantly, neither model requires consistent changes in RNA species.

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.

The potential of sertoli cells (SCs) derived exosomes and its therapeutic efficacy in male reproductive disorders

In the male reproductive system, seminiferous tubules in testis are lined by a complex stratified epithelium containing two distinct populations of cells, spermatogenic cells that develop into spermatozoa, and sertoli cells (SCs) that mainly support and nourish spermatogenic cell lineage as well as exerting powerful effect on men reproductive capacity. Different varieties of proteins, hormones, exosomes and growth factors are secreted by SCs. There are different kinds of junctions found between SCs called BTB. It was elucidated that complete absence of BTB or its dysfunction leads to infertility. To promote spermatogenesis, crosstalk of SCs with spermatogenic cells plays an important role. The ability of SCs to support germ cell productivity and development is related to its various products carrying out several functions. Exosomes (EXOs) are one of the main EVs with 30-100 nm size generating from endocytic pathway. They are produced in different parts of male reproductive system including epididymis, prostate and SCs. The most prominent characteristics of SC-based exosomes is considered mutual interaction of sertoli cells with spermatogonial stem cells and Leydig cells mainly through establishment of intercellular communication. Exosomes have gotten a lot of interest because of their role in pathobiological processes and as a cell free therapy which led to developing multiple exosome isolation methods based on different principles. Transmission of nucleic acids, proteins, and growth factors via SC-based exosomes and exosomal miRNAs are proved to have potential to be valuable biomarkers in male reproductive disease. Among testicular abnormalities, non-obstructive azoospermia and testicular cancer have been more contributed with SCs performance. The identification of key proteins and miRNAs involved in the signaling pathways related with spermatogenesis, can serve as diagnostic and regenerative targets in male infertility.

Coding and regulatory transcriptome comparisons between fertile and infertile spermatozoa identify RNA signatures of male infertility

The aim of the present study was to identify RNA-based signatures of male infertility by sperm transcriptome analysis. In this study, deep sequencing analyses of coding (mRNA) and regulatory (miRNA) transcriptomes were performed by pooling 15 oligo/oligoasthenozoospermic infertile sperm and 9 normozoospermic fertile sperm samples. Furthermore, interesting candidates were selected for validation by real-time PCR. The comparison of miRNAs between cases and controls identified 94 differentially expressed miRNAs, of which at least 38 have known functions in spermatogenesis. In transcriptome (mRNA) data, a total of 60,505 transcripts were obtained. The comparison of coding RNAs between cases and controls revealed 11,688 differentially expressed genes. miRNA-mRNA paired analysis revealed that 94 differentially expressed miRNAs could potentially target 13,573 genes, of which 6419 transcripts were actually differentially expressed in our data. Out of these, 3303 transcripts showed inverse correlation with their corresponding regulatory miRNAs. Moreover, we found that most of the genes of miRNA-mRNA pairs were involved in male germ cell differentiation, apoptosis, meiosis, spermiogenesis and male infertility. In conclusion, we found that a number of sperm transcripts (miRNAs and mRNAs) have a very high potential of serving as infertility/sperm quality markers.

The Role of Seminal Oxidative Stress Scavenging System in the Pathogenesis of Sperm DNA Damage in Men Exposed and Not Exposed to Genital Heat Stress

Responding to the need for the verification of some experimental animal studies showing the involvement of oxidative stress in germ cell damage in the heat-induced testis, we investigated the possibility of a direct relationship between seminal oxidative stress markers (total antioxidant capacity, catalase activity, superoxide dismutase activity, and malondialdehyde concentration) and ejaculated sperm chromatin/DNA integrity (DNA fragmentation and chromatin condensation abnormalities) in distinct groups of men exposed and not exposed to prolonged scrotal hyperthermia. A statistical increase in the proportion of sperm with DNA fragmentation was observed in all the studied subgroups compared to the fertile men. In turn, the groups subjected to heat stress as professional drivers or infertile men with varicocele presented greater disturbances in the oxidative stress scavenging system than men not exposed to genital heat stress. Based on the comparative analysis of the studied parameters, we can conclude that alterations in the seminal oxidative stress scavenging system are directly engaged in the pathogenesis of ejaculated sperm DNA damage regardless of the intensity of the impact of thermal insult. To the best of our knowledge, this study, for the first time, revealed the co-existence of oxidative stress and sperm DNA damage in the semen of professional drivers.

Heat treatment reduced the expression of miR-7-5p to facilitate insulin-stimulated lactate secretion by targeting IRS2 in boar Sertoli cells

Insulin dysfunction of diabetes mellitus (DM) disorders the glucose metabolism in Sertoli cells (SCs), resulting in the impairment of spermatogenesis.Insulin signaling system in Sertoli cells (SCs) plays an important role in regulating lactate secretion. Heat treatment could increase the lactate secretion of boar SCs, but whether heat treatment participates in lactate secretion by improving the sensitivity of insulin is unknown. In the current study, the primary SCs from 21-day-old boar were employed to treat with 100 nM insulin for 24 h or heat treatment (43 °C, 30 min). Heat treatment strengthened the effect of insulin on the effect of lactate secretion. In addition, heat treatment increased the expression of insulin-induced insulin receptor substrate 2 (IRS2), but reduced the expression of miR-7-5p. Using dual luciferase reporter assay and Western blot, the study found that IRS2 is a potential target gene of miR-7-5p. Heat treatment also enhanced the Phosphorylation of insulin-stimulated PI3K/Akt, and increased lactate secretion by promoting the expression of Glucose Transporter 3 (GLUT3), Lactate Dehydrogenase-A (LDHA) and monocarboxylate transporter 1 (MCT1). Furthermore, miR-7-5p inhibitor could partly mimic the effects of heat treatment on lactate production of SCs, indicating that heat treatment improves insulin sensitivity by regulating the expression of miR-7-5p/IRS2/PI3K/Akt. These results reveal a novel miRNA-mediated mechanism of heat treatment on the regulation of lactate metabolism production, and suggest that targeting miR-7-5p is a probably therapeutic method to insulin dysfunction-induced metabolic diseases.

Hepatitis B Virus-Encoded MicroRNA (HBV-miR-3) Regulates Host Gene PPM1A Related to Hepatocellular Carcinoma

BACKGROUND

Hepatitis B is a liver infection disease caused by the Hepatitis B Virus (HBV) that can become chronic and develop into hepatocellular carcinoma. HBV was classified as a double-stranded DNA virus. Currently, there is a report showing that HBV virus-encoded miRNA called HBV-miR-3 controls the replication of HBV. However, the regulation of HBV-miR-3 in host cells remains unclear.

OBJECTIVE

This study aimed to investigate the regulation of HBV-miR-3 in host gene target which is related to chronic HBV infection and HCC process.

METHODS

In this study, we analyzed the read count of HBV-miR-3 from next-generation sequencing of chronic hepatitis patients in Pegylated interferon alpha-2a (PEG-IFN-α-2a) treatment. To understand the regulation of HBV-miR-3 in host cells, the HBV-miR-3 recognition sites were predicted in host target genes using miRDB. The effect of HBV-miR-3 in host cells was examined using qPCR and 3' UTR dual luciferase assay.

RESULTS

The read count of HBV-miR-3 was found in chronic hepatitis patients before treatment. Moreover, the decrease of HBV-miR-3 was correlated with response group of chronic hepatitis patients after treatment. On the other hand, the abundance of HBV-miR-3 showed no difference in nonresponse group of chronic patients after PEG-IFN-α-2a treatment. To study the role of HBV-miR-3 in patients, four HBV-miR-3 target regions from Protein phosphatase 1A (PPM1A) and DIX domain containing 1 (DIXDC1) were identified in the human genome using miRDB. Interestingly, we found that HBV-miR-3 hybridized with PPM1A mRNA. The mRNA expression from RT-qPCR showed no difference between HepG2 transfected with pSilencer_scramble or pSilencer_HBV-miR-3. However, the reporter assay showed that PPM1A mRNA was suppressed by HBV-miR-3. The protein expression of PPM1A showed a decrease in cells overexpressing HBV-miR-3. Finally, the HBV-miR-3 can promote cell proliferation in cells overexpressing HBV-miR-3.

CONCLUSION

This study is the first report showed the HBV encoded miRNA can regulate host gene expression. HBV-miR-3 silenced PPM1A by inhibiting the translation process of PPM1A. The downregulation of PPM1A promotes cell proliferation related to HCC development.

Upregulated microRNA-423-5p promotes oxidative stress through targeting glutathione S-transferase mu 1 in asthenozoospermia

The dysregulation of microRNAs (miRNAs) plays an important role in asthenozoospermia. This study evaluated the sperm microRNA-423-5p (miR-423-5p) expression in asthenozoospermia and normozoospermia, exploring the role of miR-423-5p in asthenozoospermia. Eighty participants were divided into asthenozoospermic (AZS, n = 40) and normozoospermic (Norm, n = 40) groups. Fresh semen samples were collected and the sperm cells were separated. Quantitative Real-Time polymerase chain reaction was used to measure the sperm miR-423-5p level. Receiver operating characteristic curve (ROC) was employed to test the diagnostic performance of miR-423-5p in asthenospermia. Dual-reporter luciferase assay was adopted to confirm the target gene of miR-423-5p. The target gene level in asthenozoospermia and normozoospermia was measured, and the biological function of target gene in asthenozoospermia was evaluated. Results showed that the miR-423-5p expression level in the AZS group was higher than that in Norm group, which was positively correlated with the severity of asthenozoospermia. ROC analysis of miR-423-5p showed an area under curve (AUC) of 0.69 (95% confidence interval = 0.57-0.80, p <0 .01), with 80% sensitivity and 60% specificity. Glutathione S-transferase mu 1 (GSTM1) is a target gene of miR-423-5p, which significantly decreased in the AZS group. Compared with Norm group, glutathione S-transferase (GST) activity and total antioxidant capacity (TAC) level decreased, while malondialdehyde (MDA) level increased in the AZS group. Furthermore, GST activity and TAC level were negatively correlated with miR-423-5p expression, while MDA level was positively correlated with miR-423-5p expression. In conclusion, the sperm miR-423-5p level significantly was upregulated in asthenozoospermia. High-level miR-423-5p inhibited sperm motility through targeting GSTM1 to promote oxidative stress.

Potential role of specific microRNAs in the regulation of thermal stress response in livestock

Thermal stress is known to have harmful effects on livestock productivity and can cause livestock enterprises considerable financial loss. These effects may be aggravated by climate change. Stress responses to nonspecific systemic actions lead to perturbation of molecular pathways in the organism. The molecular response is regulated in a dynamic and synchronized manner that assurances robustness and flexibility for the restoration of functional and structural homeostasis in stressed cells and tissues. MicroRNAs (miRNAs) are micro molecules of small non-coding RNA that control gene expression at the post-transcriptional level. Recently, various studies have discovered precise types of miRNA that regulate cellular machinery and homeostasis under various types of stress, suggesting a significant role of miRNA in thermal stress responses in animals. The miRNAs revealed in this paper could serve as promising candidates and biomarkers for heat stress and could be used as potential pharmacological targets for mitigating the consequences of thermal stress. Stress miRNA pathways may be associated with thermal stress, which offers some potential approaches to combat the negative impacts of thermal stress in livestock. The review provides new data that can assist the elucidation of the miRNA mechanisms that mediate animals' responses to thermal stress.

The role of miR-128-3p through MAPK14 activation in the apoptosis of GC2 spermatocyte cell line following heat stress

BACKGROUND

MicroRNAs play a crucial role in the regulation of spermatogenesis. For example, miR-128-3p expression is known to decrease significantly after testicular hyperthermia, but the regulatory effect of this change on the spermatogenesis damage caused by heat stress remains unclear.

OBJECTIVES

This study aimed to verify whether the target gene of miR-128-3p is MAPK14, which affects spermatogenic cell proliferation and apoptosis under testicular hyperthermia.

MATERIALS AND METHODS

Mouse testis and GC2 spermatocyte cell line heat stress models were established. miR-128-3p expression before and after heat stress was analyzed by reverse transcription polymerase chain reaction. MAPK14 and p-MAPK14 expression was detected by Western blot, and cell apoptosis was analyzed by Annexin V-FITC/PI. Subsequently, miR-128-3p inhibitors and mimics were used to interfere with spermatocytes before and after heat stress, respectively, for correlation detection.

RESULTS

Compared with the control group, the heat stress group showed decreased miR-128-3p expression, increased p-MAPK14 expression, and decreased cell proliferation activity. In the GC2-spd cell line in vitro, miR-128-3p inhibitors were found to upregulate p-MAPK14 expression, reduce cell proliferation activity, and increase apoptosis, consistent with the results obtained in the heat treatment alone. Furthermore, miR-128-3p mimics transfected in the GC2 cells after heat stress reduced p-MAPK14 expression, alleviated the decrease in cell proliferation, and decreased the apoptosis level.

CONCLUSIONS

The downregulation of miR-128-3p expression plays an important role in spermatogenesis damages after testicular hyperthermia, which is probably attributable to the activation of the MAPK signaling pathway. Downregulated miR-128-3p expression induces the apoptosis and inhibits the proliferation of spermatogenic cells by promoting MAPK14 phosphorylation.

Oxidative stress-related miRNAs in spermatozoa may reveal the severity of damage in grade III varicocele

Varicocele is associated with excessive production of reactive oxygen species (ROS). Although the harmful effects of ROS on sperm DNA, proteins and lipids are well documented, its impact on the expression of miRNAs in spermatozoa has not been fully understood. In this study, the expression patterns of microRNAs (miRNAs), miR-21, miR-34a and miR-122a as well as the level of ROS in the fertile control (FC; proven fertility without varicocele, n = 15) and grade III varicocele patients with normal (VN; n = 15) and abnormal (VA; n = 15) spermogram were investigated. The real-time PCR was performed to analyse the expression of the miRNAs, while oxidative stress was evaluated by measuring the concentrations of MDA. Our results showed that the expression levels of miR-21 (p = .001), miR-34a, (p = .007) and miR-122a (p < .001) were significantly decreased in spermatozoa of VN and VA patients in comparison with the fertile group. Also, increased levels of oxidative stress were detected in semen samples of varicocele patients compared with the fertile control (p < .0001). Overall, these findings demonstrate oxidative stress changes the expression pattern of some miRNAs, and these alterations could be a valuable diagnostic marker for the diagnosis and prognosis of varicocele-induced oxidative stress to retain the male fertility during the spermatogenesis process.

Exploration of small RNA biomarkers for testicular injury in the serum exosomes of rats

Testicular injury is often observed in drug development. Serum hormones are usually used as noninvasive biomarkers for testicular injury; however, their sensitivities are low. Therefore, it is difficult to monitor testicular injury in drug development. In recent years, molecules in body fluid exosomes have attracted attention as biomarkers for diseases. In this study, small RNAs in serum exosomes were analyzed to identify noninvasive biomarkers of testicular injury in rats, which are often used in preclinical drug development. The rat models of testicular injury were prepared by a single oral administration of 2000 mg/kg ethylene glycol monomethyl ether, in which spermatocyte degeneration and Sertoli cell vacuolation were observed, or 400 mg/kg carbendazim, in which Sertoli cell vacuolation and seminiferous tubule dilation were observed. Serum exosomal small RNA-seq analysis of these models was performed. The analysis identified 3 small RNAs that fluctuated in common between the models, and miR-423-5p and miR-128-3p were selected as candidate markers. For evaluating these candidate markers in other testicular injury models, the models were prepared by a single oral administration of 60 mg/kg 1,3-dinitrobenzene or 500 mg/kg nitrofurazone, and spermatocyte degeneration and Sertoli cell vacuolation were observed. In qPCR analysis, these exosomal miRNAs were upregulated in all models except for the 1,3-dinitrobenzene model, in which severe hemolysis was observed. By contrast, these miRNAs in whole serum extracts did not significantly change in any of the models. In conclusion, we identified miR-423-5p and miR-128-3p in serum exosomes as noninvasive biomarkers for testicular injury in rats.