The Enhancement of Sperm Retrieval Rate in Cases of Non-Obstructive Azoospermia Via Collagenase IV Enzyme Treatment in Combination with Mechanical Extraction

In cases of non-obstructive azoospermia (NOA), enzymatic digestion and mechanical treatment can be applied for the extraction of vital spermatozoa from the testicular tissues obtained by the microscopic testicular sperm extraction (micro TESE) surgery. Unfortunately, the results have repeatedly proven to be unsatisfactory when using either method separately. This study aimed at increasing the sperm retrieval rate of testicular sperm extraction (TESE), by using enzymatic digestion using collagenase IV in combination with sperm extraction from a testis tissue with mechanical method. To estimate this, tissue samples were collected from 146 men with NOA who underwent unsuccessful TESE using the mechanical method for sperm extraction. After the micro TESE, the mechanical procedures by mincing and shredding combined with   enzymatic digestion using DNaseI and collagenase type IV was applied to the samples. Pathology, testis size and hormones were determined for all patients.The combination of micro TESE and enzymatic digestion can now be foreseen as an effective method to recover spermatozoa.

Key words: TESE, Micro TESE, Non-obstructive azoospermia (NOA), enzymatic digestion, collagenase IV