Antioxidants and Oxidants in Boar Spermatozoa and Their Surrounding Environment Are Associated with AMPK Activation during Liquid Storage

Junwei Li; Wenming Zhao; Jiaqiao Zhu; Huiming Ju; Ming Liang; Shuaibiao Wang; Shufang Chen; Graça Ferreira-Dias; Zongping Liu

doi:10.3390/vetsci10030214

Antioxidants and Oxidants in Boar Spermatozoa and Their Surrounding Environment Are Associated with AMPK Activation during Liquid Storage

Vet Sci. 2023 Mar 10;10(3):214. doi: 10.3390/vetsci10030214.

Authors

Junwei Li^{1

2}, Wenming Zhao^{1

2}, Jiaqiao Zhu^{1

2}, Huiming Ju^{1

2}, Ming Liang³, Shuaibiao Wang^{4

5}, Shufang Chen⁶, Graça Ferreira-Dias^{7

8}, Zongping Liu^{1

2}

Affiliations

¹ College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China.
² Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
³ Department of Feeding Microecology, Shandong Baolaililai Bioengineering Co., Ltd., Tai'an 271001, China.
⁴ DanAg Agritech Consulting (Zhengzhou) Co., Ltd., Zhengzhou 450000, China.
⁵ Royal Veterinary College, London NW1 0TU, UK.
⁶ Ningbo Academy of Agricultural Science, Ningbo 315040, China.
⁷ CIISA-Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal.
⁸ Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisbon, Portugal.

Abstract

Activation of the AMP-activated protein kinase (AMPK) has been demonstrated to be beneficial for boar sperm quality and functionality, while the underlying mechanism of AMPK activation of boar spermatozoa remains obscure. This study aimed to explore the effect of antioxidants and oxidants in boar spermatozoa and their surrounding fluid (SF) on the activation of AMPK during the liquid storage. Ejaculates from Duroc boars, routinely used for semen production, were collected and diluted to a final concentration of 25 × 10⁶/mL. In experiment 1, twenty-five semen samples from eighteen boars were stored at 17 °C for 7 days. In experiment 2, three pooled semen samples created from nine ejaculates of nine boars were used, and each sample was treated with 0, 0.1, 0.2, and 0.4 μM/L H₂O₂ and stored at 17 °C for 3 h. Sperm quality and functionality, antioxidants and oxidants in boar spermatozoa and SF, the intracellular AMP/ATP ratio, and the expression levels of the phosphorylated AMPK (Thr172) were determined. Sperm quality significantly decreased with storage time in terms of viability (p < 0.05). Antioxidant and oxidant levels were markedly affected with storage time, with a decline in the SF total antioxidant capacity (TAC) (p < 0.05), SF malondialdehyde (MDA) (p < 0.05), and the sperm's total oxidant status (TOS), as well as a fluctuation in sperm superoxidase dismutase-like (SOD-like) activity (p < 0.05). The intracellular AMP/ATP ratio increased (p < 0.05) on day 4 and subsequently decreased to its lowest value on days 6 and 7 (p < 0.05). The phosphorylated AMPK levels increased from day 2 to day 7 (p < 0.05). Correlation analyses indicate that sperm quality during liquid storage was correlated to antioxidants and oxidants in spermatozoa and SF (p < 0.05), which were correlated to the phosphorylation of sperm AMPK (p < 0.05). Treatment with H₂O₂ induced damages in sperm quality (p < 0.05), a decline in antioxidant levels (SF TAC, p < 0.05; sperm SOD-like activity, p < 0.01), an increase in oxidant levels (SF MDA, p < 0.05; intracellular ROS production, p < 0.05), a higher AMP/ATP ratio (p < 0.05), and phosphorylated AMPK levels (p < 0.05) in comparison with the control. The results suggest that antioxidants and oxidants in boar spermatozoa and SF are involved in AMPK activation during liquid storage.

Keywords: AMPK activation; antioxidants; boar semen; liquid storage.

Abstract

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