Carboxylated ε-Poly-L-Lysine Supplementation of the Freezing Extender Improves the Post-Thawing Boar Sperm Quality

Abstract

Frozen boar sperm is used on a minimal scale in consequence of the cryo-injuries induced by biochemical and physical modifications during the freezing and thawing processes. The present study investigates whether the addition of carboxylated ε-poly-L-lysine (CPLL) to the freezing medium could improve post-thaw boar sperm quality or not. Boar sperm was diluted with freezing medium contained different doses of carboxylated ε-poly-L-lysine (0, 0.125%, 0.25%, 0.5%, and 1%; v/v). The motility patterns, membrane integrity, acrosome integrity, mitochondrial membrane potential, NADH-CoQ activity, ATP level, malondialdehyde (MDA) level, and antioxidant defense system, as well as apoptosis in post-thaw boar sperm, were measured. It was observed that 0.25% CPLL treatment significantly improved the post-thaw boar sperm total motility, progressive motility, straight-linear velocity (VSL), curvilinear velocity (VCL), average path velocity (VAP), linearity (LIN), straightness (STR), membrane integrity, and acrosome integrity. Interestingly, the addition of CPLL also significantly increased the post-thaw sperm mitochondrial membrane potential, NADH-CoQ activity, and ATP level. Moreover, post-thaw boar sperm catalase (CAT) activity, glutathione peroxidase (GPx) activity, and superoxide dismutase (SOD) activity were increased with the addition of CPLL from 0.125% to 0.5% concentration levels. Furthermore, reduction of post-thaw sperm MDA level and apoptosis in 0.25% CPLL treatment was also observed. Those observations suggested that the addition of 0.25% CPLL to the freezing medium increased post-thaw boar sperm quality by protecting sperm mitochondrial function and antioxidant defense system. These findings provided novel insights that CPLL can be used as an efficient cryoprotectant to improve the post-thaw boar sperm quality during cryopreservation.

β-Nicotinamide mononucleotide improves chilled ram sperm quality in vitro by reducing oxidative stress damage

“…For detection, images were acquired using a digital camera (acA780-75gc; Basler, Allensburg, Germany) and a negative phase contrast microscope at 100× magnification, set to a standard parameter of 25 frames/s. According to our previous study [18], after preheating the analyzer, semen sample aliquots of 5 μL were added to the Makler chamber. Sperm motility was assessed in three randomly selected areas using CASA, and a total of 500 sperm were evaluated.…”

“…MDA is one of the final products of polyunsaturated fatty acids (PUFA) peroxidation in cells, which is regarded as a marker of oxidative stress. According to Zhang et al [18], a commercial MDA assay kit (S0131S; Beyotime Institute of Biotechnology, Shanghai, China) was used to measure MDA content. Sperm stored at 4°C were lysed by sonication (20 kHz, 300 W, operating at 50%, 3 min for 10 s on and 5 s off) on ice.…”

Resveratrol Improves the Frozen-Thawed Ram Sperm Quality

“…The post-thaw sperm was diluted with Tris-citratefructose extender before motility evaluation. According to our previous study [23], after preheating the analyzer, semen sample aliquots of 5 µL were added to the Makler chamber. Sperm motility was then assessed in three randomly selected areas using CASA, and more than 500 sperm were evaluated.…”

“…The ATP content in sperm was measured using an ATP content assay kit (A095-1-1; Nanjing Jiancheng Bioengineering; Wuhan, China) [23]. Additionally, 30 µL of semen was centrifuged at 800× g for 5 min, and the supernatant was discarded while the bottom layer of precipitated cells was collected.…”

Animal Reproduction: Semen Quality Assessment

“…Frozen semen is rarely used in the artificial insemination of pigs due to its low quality after thawing. A study by Zhang et al [ 9 ] investigated the effect of adding carboxylated ε-poly-L-lysine (CPLL) to semen extender as a cryoprotectant. The addition of 0.25% CPLL to the extender for freezing was found to significantly improve sperm motility, cell membrane integrity, mitochondrial function, and the antioxidant capacity of sperm after thawing.…”