Tag Archives: spermatozoa

Lipid peroxidation and DNA fragmentation in fresh and cryopreserved spermatozoa of men at different spermatogenesis state

T. O. Yurchuk*, O. V. Pavlovich, G. O. Gapon,
A. Y. Pugovkin, M. P. Petrushko

Institute for Problems of Cryobiology and Cryomedicine, National Academy of Sciences of Ukraine, Department of Cryobiology of Reproductive System, Kharkiv;
*e-mail: taisiya.yur@gmail.com

Received: 11 July 2021; Accepted: 17 May 2021

Cryopreservation of spermatozoa is widely used in the treatment of infertility by assisted reproductive technologies. However, the cryopreservation causes an oxidative stress which can induce pathological changes in the male gametes. The aim of the research was to evaluate lipid peroxidation (LPO) and DNA fragmentation as well as correlation between these parameters in the fresh and cryopreserved spermatozoa of men with normozoospermia or oligoasthenoteratozoospermia (OAT) and spermatozoa derived from the epididymis of men with azoospermia. The level of malondialdehyde (MDA) in a TBA test, superoxide dismutase (SOD) activity and total antioxidant activity (AOA) were assessed. DNA integrity was estimated by acridine orange staining technique. It was shown that MDA level and SOD activity were significantly higher in the fresh spermatozoa of oligoasthenoteratozoospermic group compared with the fresh spermatozoa of normozoospermic group. After cryopreservation the MDA level increased in all groups and was the highest in OAT group where the greatest AOA decline was detected. DNA fragmentation frequency was 2.6 and 4.1 times higher in the fresh and cryopreserved OAT spermatozoa respectively as compared with the fresh normozoospermic ones (7.2%). DNA fragmentation was found to be the lowest in the fresh (6.2%) and cryopreserved (5.8%) epididymal spermatozoa. After cryopreservation SOD activity in epididymal spermatozoa was lower than in  normozoaspermic. In spermatozoa of the studied groups the MDA level positively correlated with DNA fragmentation (0.79 Pearson’s correlation coefficient) both before and after cryopreservation. It is suggested that due to the detected low DNA fragmentation and LPO level in epididymal spermatozoa their use could be an alternative approach for infertility treatment by assisted reproductive technologies.

Responsiveness to progesterone and potassium channel blockers 4-aminopyridine, tetraethylammonium and free Ca(2+) contentration in spermatozoa of patients with oligozoospermia/leucocytospermia

R. V. Fafula1, G. V. Danylovych2, A. S. Besedina1, O. V. Melnyk1, Z. D. Vorobets1

1Danylo Halytsky Lviv National Medical University, Ukraine;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: roman_fafula@ukr.net

The present study was undertaken to evaluate [Ca2+]i signals that occur in human sperm cells exposed in vitro to three diverse compounds; progesterone, 4-aminopyridine (a highly effective inducer of hyperactivation in human sperm) and tetraethylammonium. The [Ca2+]i reached after the extracellular calcium treatment was always higher in normozoospermic samples pretreated with progesterone than in pathozoospermic samples pretreated with progesterone. There were no changes in calcium signal in spermatozoa pretreated with progesterone from patients with oligozoospermia and leucocytospermia compared to control samples (without progesterone). [Ca2+]i was always higher in pathozoospermic samples without 4-aminopyridine and always lower in pathozoospermic samples with 4-aminopyridine compared to these values in normozoospermic men. The 2 mM extracellular calcium administration to spermatozoa pretreated with tetraethylammonium did not result in a detectable increase in [Ca2+]i in normo- and pathozoospermic samples. The mechanisms of progesterone-dependent activation of the Ca2+-entry and the functioning of the voltage gated Ca2+-channels of plasmalemma are disturbed in pathologies – there was no increase in the Ca2+ level in the conditions of K+-depolarization (in the presence of inhibitors of K+-channels).