To compare oxidative stress in human testicular tissue in both cases of obstructive (OA) and non- obstructive or functional azoospermia (NOA) before and after cryopreservation.
Design:
Comparative study.
Material and methods:
Azoospermic patients with OA and NOA were subject to surgical sperm retrieval with needle aspiration using a 14 G cannula. Cryopreservation was done in cryovials immersed in liquid nitrogen(-196⁰c). Assay of Catalase activity (CAT) and Malondialdehyde level (MDA) using colorimetric methods in fresh testicular samples and after cryopreservation of samples with positive sperm retrieval. In addition, assessing the number of retrieved sperms and Johnson spermatogenic score were done in fresh testicular samples.
Results:
The study included 21 OA (group A), 16 positive NOA (group B with positive sperm retrieval) and 21 negative NOA (group C with negative sperm retrieval). Mean CAT activity in positive and negative NOA groups (151.90 ± 122.32 U/gm protein) (146.00 ± 121.7 U/gm protein respectively), were significantly higher than OA group (65.67 ± 72.99 U/gm protein) (P=0.017, P=0.018 respectively). MDA level was also significantly higher in positive and negative NOA (31.50 ± 15.81 nmolgm) (40.38 ± 14.42 nmolgm) groups than OA group (21.33 ± 9.61 nmolgm) (P=0.043, P=0.000) respectively. CAT activity and MDA level correlated negatively with mean number of retrieved sperms (in groups with positive sperm retrieval A&B) (r= - 0.261, P= 0.048, r= -0.402, P=0.002) respectively. After thaw there was significant increase in CAT activity in OA only (213.67 ± 160.36 v 65.67 ± 72.99 U/gm protein) (P= 0.000), while there was no significant difference in MDA level in both OA and positive NOA. However, after thawing mean MDA level was still significantly higher in NOA than OA (26.94 ± 11.21 v 24.19 ± 15.97 nmolgm) (P= 0.049).

Conclusion:
Men with NOA seem to have increased basal testicular oxidative stress compared to those with OA as indicated by increased CAT activity and MDA level in fresh testicular samples. These markers of oxidative stress correlated negatively with spermatogenic activity. Furthermore, OA seem to resist oxidative injury induced by cryopreservation by enhancing CAT activity more efficiently than NOA.