Methods for assessment of testicular sperm viability: a mini-review Running title: Assessment of testicular sperm viability

Document Type : Review Article

Authors

1 Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Sohag University

2 Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Sohag University, Sohag, Egypt

3 Dermatology, Venereology and Andrology Department, Faculty of Medicine, Sohag University

Abstract

Assessment of testicular sperm viability is crucial for successful intracytoplasmic sperm injection (ICSI) in cases of male infertility involving azoospermia. Traditional methods like staining cannot be used as they compromise sperm viability. This article aimed to provide a comprehensive mini-review of different methods for the assessment of testicular sperm vitality during ICSI. The hypo-osmotic swelling test (HOST) is considered the gold standard, identifying viable sperm based on membrane integrity. However, HOST has limitations with thawed samples and is technically demanding. Chemical agents like pentoxifylline can induce tail movements in immotile sperm to facilitate selection, but with potential toxicity concerns. The sperm tail flexibility test (STFT) relies on mechanically manipulating the tail to detect viability. Laser-assisted immotile sperm selection (LAISS) is an emerging technique using laser pulses to induce tail movements in viable sperm without chemicals. Birefringence polarization microscopy distinguishes viable sperm based on their birefringent properties under polarized light. Raman micro-spectroscopy is a label-free method using molecular fingerprinting to identify biochemical markers of viability. Each technique has advantages and limitations in terms of efficacy, safety, cost and technical requirements. Combining multiple complementary approaches may optimize viable sperm selection for ICSI. Further research is needed to establish the relative performance and refine protocols, with the ultimate goal of improving fertilization and pregnancy outcomes for azoospermic men seeking fertility treatment.

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