Gaussian clustering and quantification of the sperm chromatin dispersion test using convolutional neural networks.

Sperm DNA fragmentation is a sign of sperm nuclear damage. The sperm chromatin dispersion (SCD) test is a reliable and economical method for the evaluation of DNA fragmentation. However, the cut-off value for differentiation of DNA fragmented sperms is fixed at 1/3 with limited statistical justification, making the SCD test a semi-quantitative method that gives user-dependent results. We construct a collection of deep neural networks to automate the evaluation of bright-field images for SCD tests. The model can detect valid sperm nuclei and their locations from the input images captured with a 20× objective and predict the geometric parameters of the halo ring. We construct an annotated dataset consisting of N = 3120 images. The ResNet 18 based network reaches an average precision (AP50) of 91.3%, a true positive rate of 96.67%, and a true negative rate of 96.72%. The distribution of relative halo radii is fit to the multi-peak Gaussian function (p > 0.99). DNA fragmentation is regarded as those with a relative halo radius 1.6 standard deviations smaller than the mean of a normal cluster. In conclusion, we have established a deep neural network based model for the automation and quantification of the SCD test that is ready for clinical application. The DNA fragmentation index is determined using Gaussian clustering, reflecting the natural distribution of halo geometry and is more tolerable to disturbances and sample conditions, which we believe will greatly improve the clinical significance of the SCD test.

Fluorescent enzyme-based biosensor for sensitive analysis of DNA damage in cryopreserved sperm.

The freeze-thaw process can induce irreversible structural and functional changes in human sperm, particularly sperm DNA damage. Selecting a more accurate and sensitive detection method for evaluating sperm DNA integrity is crucial. To accurately assess sperm DNA integrity following the freeze-thaw process and significantly improve the clinical and scientific utilization of cryopreserved sperm. In this study, we utilized a novel fluorescent biosensor, assisted by terminal deoxynucleotidyl transferase (TdT) and Endonuclease IV, to detect DNA breakpoints during sperm cryopreservation. We evaluated the biosensor's performance by comparing it with the conventional DNA fragmentation index (DFI) measured using sperm chromatin structure analysis (SCSA). The cryopreserved group exhibited a significantly higher sperm DFI compared to the fresh group. No significant difference was observed between the antioxidant group and the cryopreserved group. However, the new method revealed a significant reduction in the number of DNA breakpoints in the antioxidant group compared to the cryopreserved group. The novel biosensor demonstrated superior accuracy and effectiveness in assessing sperm DNA integrity during cryopreservation compared to the conventional SCSA method. We believe that the biosensor holds significant potential for widespread use in the field of reproductive medicine.

Roles of follicle stimulating hormone and sphingosine 1-phosphate co-administered in the process in mouse ovarian vitrification and transplantation.

Some major challenges of ovarian tissue vitrification and transplantation include follicle apoptosis induced by cryopreservation and ischemia-reperfusion injury, as well as ovarian follicle loss during post-transplantation. This research aimed to investigate the protective effects and underlying mechanisms of follicle-stimulating hormone (FSH) and Sphingosine-1-phosphate (S1P) on vitrified and post-transplantation ovaries. Ovaries from 21-day-old mice were cryopreservation by vitrification with 0.3 IU/mL FSH, 2 µM S1P, and 0.3 IU/mL FSH + 2 µM S1P, respectively, for follicle counting and detection of apoptosis-related indicators. The results demonstrated that FSH and S1P co-intervention during the vitrification process could preserve the primordial follicle pool and inhibit follicular atresia by suppressing cell apoptosis. The thawed ovaries were transplanted under the renal capsule of 6-8 week-old ovariectomized mice and removed 24 h or 7 days after transplantation. The results indicated that FSH and S1P co-intervention can inhibit apoptosis and autophagy in ovaries at 24 h after transplantation, and promote follicle survival by up-regulating Cx37 and Cx43 expression, enhanced angiogenesis in transplanted ovaries by promoting VEGF expression, as well as increased the E2 levels to restore ovarian endocrine function at 7 days after transplantation. The hypoxia and ischemia cell model was established by CoCl2 treatment for hypoxia in human granulosa-like tumor cell line (KGN), as well as serum-free culture system was used for ischemia. The results confirmed that ischemia-hypoxia-induced apoptosis in ovarian granulosa cells was reduced by FSH and S1P co-intervention, and granulosa cell autophagy was inhibited by up-regulating the AKT/mTOR signaling pathway. In summary, co-administration of FSH and S1P can maintain ovarian survival during ovarian vitrification and increase follicle survival and angiogenesis after transplantation.

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.

Oxalate-induced apoptosis through ERS-ROS-NF-κB signalling pathway in renal tubular epithelial cell.

BACKGROUND: Kidney stones are composed of approximately 70-80% calcium oxalate. However, the exact mechanism of formation of calcium oxalate kidney stones remains unclear. In this study, we investigated the roles of endoplasmic reticulum stress (ERS), reactive oxygen species (ROS), and the NF-κB signalling pathway in the pathogenesis of oxalate-induced renal tubular epithelial cell injury and its possible molecular mechanisms. METHODS: We established a model to evaluate the formation of kidney stones by intraperitoneal injection of glyoxylic acid solution into mice and assessed cell morphology, apoptosis, and the expression levels of ERS, ROS, and NF-κB signalling pathway-related proteins in mouse renal tissues. Next, we treated HK-2 cells with potassium oxalate to construct a renal tubular epithelial cell injury model. We detected the changes in autophagy, apoptosis, and mitochondrial membrane potential and investigated the ultrastructure of the cells by transmission electron microscopy. Western blotting revealed the expression levels of apoptosis and autophagy proteins; mitochondrial structural and functional proteins; and ERS, ROS, and NF-κB (p65) proteins. Lastly, we studied the downregulation of NF-κB activity in HK-2 cells by lentivirus interference and confirmed the interaction between the NF-κB signalling and ERS/ROS pathways. RESULTS: We observed swelling of renal tissues, increased apoptosis of renal tubular epithelial cells, and activation of the ERS, ROS, and NF-κB signalling pathways in the oxalate group. We found that oxalate induced autophagy, apoptosis, and mitochondrial damage in HK-2 cells and activated the ERS/ROS/NF-κB pathways. Interestingly, when the NF-κB signalling pathway was inhibited, the ERS/ROS pathway was also inhibited. CONCLUSION: Oxalate induces HK-2 cell injury through the interaction between the NF-κB signalling and ERS/ROS pathways.

Protective Effects of Nucleosides-Rich Extract from Cordyceps cicadae against Cisplatin Induced Testicular Damage.

Cisplatin (CISP) is an efficacious anticancer agent used in chemotherapy, however, the constraint to its clinical utility is the stray organ toxicity including testicular damage linked to oxidative and inflammatory cascades. This study aimed to explore the protective effect of nucleosides-rich extract from Cordyceps cicadae (NRCE) against CISP-induced testicular damage in rats. Rats were subjected to prophylactic oral administration of NRCE (50, 100 and 400 mg/kg body weight/day) for 7 days prior to testicular toxicity induced by CISP (10 mg/kg, ip) and were sacrificed after 72 h post-CISP injection. Cisplatin caused significant deficits in sperm count, viability and motility, testosterone and follicle stimulating hormone (FSH) compared to normal control. It depressed testicular activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), total antioxidant content (TAC), whereas malondialdehyde (MDA) increased remarkably. CISP considerably increased tumor necrosis factor-alpha (TNF-α) and interleukin-one beta (IL-1ß) with alterations in testis histology compared to normal control. Interestingly, NRCE pretreatment inhibited the CISP-induced alterations in reproductive indices, restored the antioxidant activities in testes as well as inflammatory mediators and histology comparable to control. Our findings demonstrate that NRCE could prevent CISP testicular damage via inhibition of oxidative stress and pro-inflammation in rats.

Relative safety of various spermatogenic stem cell purification methods for application in spermatogenic stem cell transplantation.

BACKGROUND: Spermatogonial stem cell (SSC) transplantation technology as a promising option for male fertility preservation has received increasing attention, along with efficient SSC purification technology as a necessary technical support; however, the safety of such application in patients with tumors remains controversial. METHODS: In this study, we used a green fluorescent protein mouse xenograft model of B cell acute lymphocytic leukemia. We isolated and purified SSCs from the testicular tissue of model mice using density gradient centrifugation, immune cell magnetic bead separation, and flow cytometry. The purified SSCs were transplanted into convoluted seminiferous tubules of the nude mice and C57BL/6 male mice subjected to busulfan. The development and proliferation of SSCs in the recipient testis were periodically tested, along with whether B cell acute lymphocytic leukemia was induced following SSC implantation. The genetic characteristics of the offspring obtained from natural mating were also observed. RESULTS: In testicular leukemia model mice, a large number of BALL cells infiltrated into the seminiferous tubule, spermatogenic cells, and sperm cells in the testis tissue decreased. After spermatogonial stem cell transplantation, the transplanted SSCs purified by immunomagnetic beads and flow cytometry methods colonized and proliferated extensively in the basement of the seminiferous tubules of mice; a large number of spermatogenic cells and sperm were found in recipient testicular tissue after 12 weeks of SSC transplantation. In leukemia detection in nude mice after transplantation in the three SSC purification groups, a large number of BALL cells could be detected in the blood of recipient mice 2-3 weeks after transplantation in the density gradient centrifugation group, but not in the blood of the flow cytometry sorting group and the immunomagnetic bead group after 16 weeks of observation. CONCLUSIONS: In this study, we confirmed that immunomagnetic beads and flow cytometry methods of purifying SSCs from the testicular tissue of the testicular leukemia mouse model could be safely applied to the SSC transplantation technology without concomitant tumor implantation. The results thus provide a theoretical basis for the application of tumor SSC cryopreservation for fertility preservation in patients with tumors.

[Rho/ROCK signaling pathway and anti-cryodamage ability of human sperm].

OBJECTIVE: To investigate the influence of the Rho/ROCK signaling pathway on the anti-cryodamage ability of human sperm and provide some theoretical evidence for the development of high-efficiency semen cryoprotectants. METHODS: We collected semen samples from 25 healthy males, each divided into a fresh, a normal cryopreservation control and an Rho-inhibition group. Before and after freezing, we detected sperm motility, viability, membrane integrity, morphology, DNA fragmentation index (DFI), acrosomal enzyme activity (AEA) and mitochondrial membrane potential (MMP) and determined the expressions of RhoA and ROCK proteins in the sperm by immunofluorescence staining. RESULTS: Compared with the normal cryopreservation control, the frozen-thawed sperm of the Rho-inhibition group showed significantly increased sperm motility （ ï¼»51.20 ± 7.70ï¼½% vs ï¼»57.50 ± 6.83ï¼½%, P = 0.002), survival rate ( ï¼»52.87 ± 5.07ï¼½% vs ï¼»60.24 ± 5.53ï¼½%, P = 0.001), membrane integrity (ï¼»59.78±5.56ï¼½% vs ï¼»67.10 ± 4.43ï¼½%, P = 0.001), percentage of morphologically normal sperm (ï¼»4.83 ± 1.11ï¼½% vs ï¼»7.46 ± 1.28ï¼½, P = 0.001) and MMP (56.30 ± 4.28 vs 63.11 ± 2.97, P = 0.001), but decreased DFI (ï¼»27.64 ± 6.64ï¼½% vs ï¼»18.87 ± 4.07ï¼½%, P = 0.001). There was no statistically significant difference in the AEA of the frozen-thawed sperm between the control and Rho-inhibition groups (97.65 ± 9.31 vs 98.30 ± 11.33, P > 0.05). Immunofluorescence staining revealed extensive expressions of RhoA and ROCK proteins in the head and neck of the sperm. CONCLUSIONS: The Rho/ROCK signaling pathway plays a role in the cryodamage to human sperm, and inhibiting the activity of Rho/ROCK can significantly improve the ability of sperm to resist cryodamage.

[Construction of a mouse model of spermatogonial stem cell transplant recipient by high-temperature heat stress].

OBJECTIVE: To investigate the feasibility of constructing a mouse model of spermatogonial stem cell (SSC) transplant recipient by high-temperature heat stress. METHODS: Four-week-old C57BL/6 male mice and B6(Cg)-Tyrc-2J/J coat color gene homozygous mutant male mice were heat-treated at 43 ℃ for an hour in the incubator. The best transplantation time was determined by HE staining, immunohistochemistry and TUNEL and the SSCs were transplanted into the seminiferous tubules of the mice followed by regular observation of the proliferation, differentiation and spermiogenesis of the SSCs in the testis of the recipient mice. Then the recipients were mated with age-matched normal female mice and the epigenetic features of their offspring were observed. RESULTS: After 3－5 days of high-temperature heat stress, the spermatogenic cells in the testicular seminiferous tubules of the recipient mice showed obviously decreased layers, disordered and loose arrangement, massive deletion, significant apoptosis, reduced mesenchymal cells and increased autophagy, which were basically recovered in about 12 days. At 8 weeks after transplantation, the isolated and purified SSCs were differentiated into spermatogenic cells and sperm with genetic function in the testicular seminiferous tubules of the recipient mice, and normal offspring were reproduced after natural mating. CONCLUSIONS: High-temperature heat stress can be used as an efficient method for rapid construction of the mouse model of spermatogonial stem cell transplantation recipient.