Identification of spermatogenesis in a rat sertoli-cell only model using Raman spectroscopy: a feasibility study

Rapid azoospermia classification by stimulated Raman scattering and second harmonic generation microscopy

Disease diagnosis and classification pose significant challenges due to the limited capabilities of traditional methods to obtain molecular information with spatial distribution. Optical imaging techniques, utilizing (auto)fluorescence and nonlinear optical signals, introduce new dimensions for biomarkers exploration that can improve diagnosis and classification. Nevertheless, these signals often cover only a limited number of species, impeding a comprehensive assessment of the tissue microenvironment, which is crucial for effective disease diagnosis and therapy. To address this challenge, we developed a multimodal platform, termed stimulated Raman scattering and second harmonic generation microscopy (SRASH), capable of simultaneously providing both chemical bonds and structural information of tissues. Applying SRASH imaging to azoospermia patient samples, we successfully identified lipids, protein, and collagen contrasts, unveiling molecular and structural signatures for non-obstructive azoospermia. This achievement is facilitated by LiteBlendNet-Dx (LBNet-Dx), our diagnostic algorithm, which achieved an outstanding 100% sample-level accuracy in classifying azoospermia, surpassing conventional imaging modalities. As a label-free technique, SRASH imaging eliminates the requirement for sample pre-treatment, demonstrating great potential for clinical translation and enabling molecular imaging-based diagnosis and therapy.

Application and Progress of Raman Spectroscopy in Male Reproductive System

Raman spectroscopy is a fast-developing, unmarked, non-invasive, non-destructive technique which allows for real-time scanning and sampling of biological samples in situ, reflecting the subtle biochemical composition alterations of tissues and cells through the variations of spectra. It has great potential to identify pathological tissue and provide intraoperative assistance in clinic. Raman spectroscopy has made many exciting achievements in the study of male reproductive system. In this review, we summarized literatures about the application and progress of Raman spectroscopy in male reproductive system from PubMed and Ovid databases, using MeSH terms associated to Raman spectroscopy, prostate, testis, seminal plasma and sperm. The existing challenges and development opportunities were also discussed and prospected.

Sperm Selection Procedures for Optimizing the Outcome of ICSI in Patients with NOA

Retrieving spermatozoa from the testicles has been a great hope for patients with non-obstructive azoospermia (NOA), but relevant methods have not yet been developed to the level necessary to provide resolutions for all cases of NOA. Although performing testicular sperm extraction under microscopic magnification has increased sperm retrieval rates, in vitro selection and processing of quality sperm plays an essential role in the success of in vitro fertilization. Moreover, sperm cryopreservation is widely used in assisted reproductive technologies, whether for therapeutic purposes or for future fertility preservation. In recent years, there have been new developments using advanced technologies to freeze and preserve even very small numbers of sperm for which conventional techniques are inadequate. The present review provides an up-to-date summary of current strategies for maximizing sperm recovery from surgically obtained testicular samples and, as an extension, optimization of in vitro sperm processing techniques in the management of NOA.

Novel methods to enhance surgical sperm retrieval: a systematic review

Objectives: To explore the use of novel technologies in sperm retrieval in men with azoospermia due to a production defect. Methods: We performed a Preferred Reporting Items for Systemic Reviews and Meta-Analysis (PRISMA)-compliant systemic literature review for manuscripts focussed on novel sperm-retrieval methods. We identified 30 studies suitable for qualitative analysis. Results and Conclusions: We identified multiple new promising technologies, each with its own distinct set of benefits and limitations, to enhance chances of sperm retrieval; these include the use of multiphoton microscopy, Raman spectroscopy, and full-field optical coherence tomography during a microdissection-testicular sperm extraction procedure. ORBEYE and ultrasonography technologies can also serve to better visualise areas of sperm production. Finally, artificial intelligence technology can play a role in the identification of sperm and, perhaps, better-quality sperm for use with assisted reproduction. Abbreviations: AI: artificial intelligence; ANN: artificial neural network; ART: assisted reproductive technology; 3D: three-dimensional; DNN: deep neural networks; FFOCT: full-field optical coherence tomography; H&E: haematoxylin and eosin; ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilisation; MESA: micro-epididymal sperm aspiration; MeSH: Medical Subject Heading; MPM: multiphoton microscopy; (N)OA: (non-)obstructive azoospermia; SCO: Sertoli cell-only syndrome; SRR: sperm retrieval rates; TESA: testicular sperm aspiration; (micro-)TESE: (microdissection-) testicular sperm extraction; (CE)US: (contrast-enhanced) ultrasonography.

Non-obstructive azoospermia: current and future perspectives

Infertility affects 1 in 6 couples, and male factor infertility has been implicated as a cause in 50% of cases. Azoospermia is defined as the absence of spermatozoa in the ejaculate and is considered the most extreme form of male factor infertility. Historically, these men were considered sterile but, with the advent of testicular sperm extraction and assisted reproductive technologies, men with azoospermia are able to biologically father their own children. Non-obstructive azoospermia (NOA) occurs when there is an impairment to spermatogenesis. This review describes the contemporary management of NOA and discusses the role of hormone stimulation therapy, surgical and embryological factors, and novel technologies such as proteomics, genomics, and artificial intelligence systems in the diagnosis and treatment of men with NOA. Moreover, we highlight that men with NOA represent a vulnerable population with an increased risk of developing cancer and cardiovascular comorbodities.

Raman spectroscopic analysis of testicular lamina propria predicts spermatogenesis in a mouse infertility model

The status of the testicular lamina propria (LP) is associated with spermatogenesis. The aim of this study was to determine whether Raman spectroscopy (RS) could detect material components within the LP and predict spermatogenesis. Twenty adult male mice were divided into a busulfan-treated group (n=16 mice receiving a single injection of 50mgkg-1, i.p., busulfan) and a control group (n=4 mice receiving an equivalent volume of 0.9% saline solution injected i.p.). Mice were killed 2, 4, 6 and 8 weeks after injection of busulfan or saline solution (n=1 control and 4 busulfan-treated mice at each time point). The testicular tubules were assessed by RS and compared with histopathological observations. Control tubules had raw spectral intensities below 2000 arbitrary units, whereas busulfan tubules had strengthened intensities that peaked at Week 4 (absent spermatogenesis) and returned to normal levels at Week 8 (restored spermatogenesis). The change in the LP revealed by RS occurred before the change in spermatogenesis detected by histopathology. Correspondingly, the sensitivity/specificity of RS for distinguishing busulfan-treated and control tubules at 2, 4, 6 and 8 weeks were 65.00%/70.00%, 95.00%/100.00%, 40.00%/100.00% and 25.00%/95.00% respectively. Collectively, RS could be used to evaluate the status of the LP and as a complement to histopathological evaluation to predict tubules with the potential to develop spermatogenesis for infertile patients.

Innovations in surgical management of nonobstructive azoospermia

Testicular sperm extraction (TESE) technique and intra-cytoplasmic sperm injection are breakthrough fertility treatments for men with nonobstructive azoospermia (NOA). Newer advances such as the microdissection-TESE (micro-TESE) technique have continued to build upon past success by improving sperm retrieval and minimizing the postoperative complications compared to TESE. However, even with micro-TESE, sperm retrieval success has ranged from 40% to 60% due to the technique's dependence on surgeon and embryologist experience. While postoperative complications are minimal relative to the traditional TESE technique, testicular tissue must still be extracted without the knowledge of whether sperm are present in biopsies. In this review, we discuss the innovations in the surgical management of men with NOA and describe the novel experimental approaches that can improve sperm retrieval success.