Changes in sperm function and structure after freezing in domestic cat spermatozoa

Abstract

Sperm cryopreservation allows for a long-term storage of genetic. However, changes due to factors as cold shock, osmotic and oxidative stress cause reduction in viability and fertilising ability of frozen/thawed spermatozoa. Therefore, evaluation of cryoinjury of cat spermatozoa is a key factor in achieving better cryopreservation results. This study analysed the changes in structural and functional after freezing in ejaculated domestic cats spermatozoa. Semen samples (n = 60) were analysed before and after freezing, progressive motility was determined with computer-assisted sperm analysis and viability, and acrosome intact spermatozoa, mitochondrial function and superoxide anion ( ) were assessed by flow cytometry. The results demonstrated that cryopreservation induced changes in all sperm parameters (p< 0.05). Total sperm motility, viability, acrosome integrity and mitochondrial function of fresh samples were near to 80% and decrease near to 40% in frozen/thawed spermatozoa (p < 0.05); nevertheless, in contrast to all other sperm parameters, the sperm positive with increased post/thawing (p< 0.05). In conclusion, changes in frozen/thawed spermatozoa could be related to the effect of oxidative stress due to the increase in the synthesis of and a concomitant loss of functional competence. Therefore, the evaluation of these sperm parameters could contribute to complement the analysis of fresh or frozen semen used ART.

Insights into alternative cryoprotectants to freeze sperm of domestic cats

“…Furthermore, it is important to consider that mitochondria, located in the midpiece region, are the organelles responsible for producing energy for the flagellar movement of the sperm cells and that this activity decreases when the cells are cryopreserved. (Cheuquemán et al, 2018). Consequently, morphometry can be a low-cost method for evaluating cryopreservation efficiency.…”

“…Notably, these studies were carried out with spermatozoa from the epididymis. Differences in the morphometric dimensions of fresh spermatozoa after thawing can be attributed to several events, including osmotic changes triggered by the progressive dehydration of these cells during the cryopreservation process (Cheuquemán et al., 2018; Martins & Justino, 2015), alterations in cellular compartments (Arruda et al., 2002), damage or loss of the sperm acrosome (Peña et al., 2003) and excess condensation of sperm chromatin (Álvarez et al., 2008). Considering these events, the extenders used in this experiment maintained the morphometric characteristics of the spermatozoa, except for the midpiece, which was lower in the extender with glycerol in 3% with 2% methylformamide.…”

“…In addition to the absence of species‐specific extenders, both domestic and wild cats have a high percentage of teratospermia, described as abnormal cells that are more susceptible to cryoinjuries (Fontbonne et al., 2020; Pukazhenthi et al., 2006). Furthermore, the process of cryopreservation uses molecules such as cryoprotectants that can be toxic to spermatozoa, which makes colling and freezing semen more challenging (Cheuquemán et al., 2018; Pukazhenthi et al., 1999; Souza et al., 2018). Therefore, different extenders are being tested to improve the cryopreservation results for these species (Brusentsev et al., 2018).…”

Effect of supplementation of Aloe vera extracts in cold storage media and cryopreservation of domestic cat epididymal spermatozoa

“…Evaluating sperm parameters is fundamental to understand the extent of the damage caused to the spermatozoa during cryopreservation, as well as analyzing protocols and choosing diluents, and cryoprotectants to better protect the cell mechanisms (Cheuquemán et al, 2018). The present study showed that both external cryoprotectants (egg yolk and A. vera) maintained the sperm motility during cooling, independent of the concentration of A. vera used in the diluent; however, the sperm motility after thawing was similar between the diluents composed of egg yolk or A. vera, only when the plant extract was used in the same concentration of the usual extracellular cryoprotectant, indicating that a possible cryoprotective effect on feline sperm requires concentration above 10% of A. vera.…”

Recuperação e conservação de espermatozoides epididimários: Perspectivas e aplicações na espécie felina doméstica

“…A criopreservação dos espermatozoides epididimários felinos apresenta protocolos diversificados, todavia, a preservação da motilidade pós-descongelação ainda é uma problemática (Kunkitti et al, 2017). Estudos futuros visando a compreensão da fisiologia espermática e as modificações estruturais/funcionais dos espermatozoides durante as etapas da criopreservação são necessários para minimizar as crinjurias (Cheuquemán et al, 2018). O entendimento dos fenômenos que envolve a teratozoospermia é uma lacuna que também deve ser investigada na espécie, para o melhor entendimento das diferenças metabólicas entre os gametas normais e anormais e futuramente, desenvolver protocolos específicos para animais únicos que apresentem elevadas taxas de espermatozoides pleimórficos (Terrel et al, 2010).…”