Identification of Spermatogenically Active Regions in Rat Testes by Using Narrow-band Imaging System

To evaluate the feasibility of narrow-band imaging (NBI) system in microdissection testicular sperm extraction (micro-TESE).

Firstly, we investigated angiogenic potential in human testicular specimens obtained from 48 patients who underwent micro-TESE. We then created a testicular injury model in rats with a single topical injection of cisplatin into the testes, and the testes were observed with and without NBI. To assess the relation between pathological changes and visual images, an immunofluorescence study of blood vessels in rat testes was carried out. We finally conducted an experiment that assumed micro-TESE by using a nonobstructive azoospermia (NOA) rat model induced by busulfan.

The number of blood vessels in the specimens of hypospermatogenesis was significantly greater than that in the specimens of maturation arrest and Sertoli cell only. In rat testes, cisplatin caused atrophic changes, and significant differences in visual color between atrophic and normal lesions were noted using NBI. The number of seminiferous tubules with spermatozoa in atrophic regions was significantly lower than that in normal regions, and a significantly small number of blood vessels in atrophic regions was also noted compared with that in normal regions. NBI also identified patchy spermatogenesis in the busulfan-induced NOA rat model.

An NBI system can distinguish spermatogenically active regions through the visualization of blood vessels in rat testes. This system may have the potential to provide useful information during micro-TESE for men with NOA.