Ultrastructure of fresh and post thawed sperm of pejerrey Odontesthes bonariensis (Atheriniformes)

Abstract

In the present study it was showed for the first time the ultrastructural morphology of O. bonariensis sperm using electron microscopy techniques. Different kinds of abnormalities were described in fresh and post thawed sperm caused by crogenic protocols. Pejerrey spermatozoon is uniflagellated and is differentiated into three parts: a small roundish head (~1.80µm in length and 1.67µm in width), a midpiece or transitional region (~1.11µm in length and 1.56µm in width), and a long tail or flagellum (~29.08µm). Samples of fresh and post thawed sperm showed evidence of morphological anomalies affecting various intracellular compartments. Spermatozoa with swollen, ruptured, or absent membranes in the head showing excess of cytoplasm, and with alteration of the spatial orientation of the mitochondria were observed. A swollen flagellum was observed containing cytoplasmic vesicles, distributed along the whole length or concentrated in a restricted part of the tail. It was also found a high level of abnormalities (60%) in frozen sperm when compared with normal sperm (18%) reflecting the damage provoked by cryopreservation procedures.No presente estudo mostrou-se pela primeira vez a morfologia estrutural dos espermatozoides de O. bonariensis utilizando técnicas de microscopia eletrônica. Diferentes tipos de anormalidades foram descritas para sêmen fresco e descongelado. O espermatozoide de Pejerrey é uniflagelado e dividido em três partes: uma cabeça pequena e arredondada (~1.80µm de comprimento e 1.67µm de largura), uma parte intermediária ou região de transição (~1.11µm de comprimento e 1.56µm de largura) e uma cauda longa ou flagelo (~29.08µm). Amostras de sêmen fresco e descongelado mostraram evidências de anormalidades morfológicas afetando vários compartimentos intracelulares. Na cabeça haviam espermatozoides com membranas dilatadas, rompidas ou ausentes, mostrando excesso de citoplasma e alteração na orientação espacial das mitocôndrias. Um flagelo dilatado foi observado contendo vesículas citoplasmáticas, as quais estavam distribuídas ao longo de todo o seu comprimento ou concentradas em uma parte restrita da cauda. Também foi encontrado um alto nível de anormalidades (60%) em sêmen congelado em comparação com o sêmen normal (18%), refletindo os danos provocados pelos procedimentos de criopreservação.

Changes in oxidative stress and ultrastructure of the sperm of silver barb, Barbonymus gonionotus , related to cryopreservation using a dry shipper

“…The vesicular‐swollen and swollen mitochondria exhibit a vacuolization and disruption of the cristae and expansion of matrix space. The moderate to severe ultrastructural damage in the mitochondria observed in post‐thawed silver barb sperm was similar to that reported in cryopreserved sperm of Atlantic salmon, pejerrey, and mammals (Díaz et al, 2019; Gárriz & Miranda, 2013; Keskin et al, 2020). Mitochondrial ultrastructural damage affecting the reduction in mitochondrial membrane potential (MMP) would lead to a decrease in the ATP content and sperm motility of post‐thawed sperm (Hasanah et al, 2020).…”

“…Sperm cells have more chance to expose the oxidative stress after spermiation and collection, which associate the degenerative mechanism and result of the apoptosis and necreosis‐related events (Beirão et al, 2019). Therefore, the presence of defective sperm with the alteration of sperm morphology such as loose plasma membrane, plasma membrane blebbing, swollen mitochondria, and altered chromosome could be observed in the fresh sperm of various fish species (Gárriz & Miranda, 2013; Moharram et al, 2014; Ninhaus‐Silveira et al, 2006; Valcarce et al, 2016; Verma et al, 2009; Viveiros et al, 2012).…”

Cryopreservation of Sterlet, Acipenser ruthenus Spermatozoa: Evaluation of Quality Parameters and Fine Ultrastructure

“…Various abnormalities, such as swelling or rupture of the plasma membrane in the flagellum and midpiece, swelling of mitochondria, change of the position of the mitochondria, loss of mitochondrial crests, vacuolization and rupture of axonemes were observed in cryopreserved spermatozoa of Atlantic croaker Micropogonias undulatus (Gwo and Arnold, 1992), grayling Thymallus thymallus (Lahnsteiner et al, 1992), rainbow trout (Lahnsteiner et al, 1996), flounder Paralichthys olivaceus (Zhang et al, 2003), striped bass Morone saxatilis (He and Woods, 2004), pejerrey Odontesthes bonariensis (Gárriz and Miranda, 2013), and Atlantic salmon (Figueroa et al, 2019). The ruptured plasma membrane of the flagellum and deformed region of the midpiece may be caused by an osmotic regulation deficiency or by leakage of the plasmalemma due to changes in its molecular structure mediated by osmotic shock and/or intracellular ice crystals (Grout and Morris, 1987).…”

“…These changes, including swelling or rupture of the tail, and certain lesions on other organelles can lead to displacement of mitochondria or loss of their function (Taddei et al, 2001). In addition, damage to spermatozoa membrane may also result from cryoprotectant toxicity, duration of exposure, and interactions with phospholipids in the membrane (Gárriz and Miranda, 2013). Changes in head shape and chromatin condensation of vacuoles and tail region have been demonstrated as a result of structural damage in cryopreserved carp spermatozoa (Drokin et al, 2003).…”

Cryopreservation of Chirostoma jordani sperm, fish model for the conservation of the genus in Mexico

“…Higher and lower concentrations of DMSO 10% and MeOH 10% and EG 14% decrease post‐thaw motility. This decrease has been related to cryoprotectant toxicity, concentration, and exposure time in species such as: Paralichthys adspersus (Catcoparco et al., 2019), Plagiognathus microlepis (Du et al., 2018), Sorubim cuspicaudus (Atencio‐García et al., 2014), C. carpio (Irawan et al., 2010), Brycon amazonicus (Cruz‐Casallas et al., 2006) and Odontesthes bonariensis (Gárriz & Miranda, 2013) a South American species belongs to Atherinopsidae.…”