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ABSTRACT:In this study, we evaluated the effects of glutathione (L-␥-glutamyl-L-cysteinylglycine; GSH) supplementation of the freezing extender on semen parameters during the cooling (2 hours at 5ЊC) and freezing phases of the cryopreservation process to compensate for the decrease in GSH content observed during sperm freezing. To fully address these questions, we incorporated a new set of functional sperm tests. These included tests of mitochondrial function, inducibility of the acrosome reaction, in vitro penetration (IVP) of oocytes, changes in sulfhydryl group content in membrane proteins, and capacitation status. The main findings emerging from this study were that the addition of GSH to the freezing media resulted in 1) an improvement in percent motility (%MOT) and motion parameters of thawed spermatozoa, as measured by both microscopic analysis and computer-assisted semen analysis (CASA); 2) a higher number of total viable spermatozoa; 3) a higher number of noncapacitated viable spermatozoa; and 4) a decrease in the number of spermatozoa with changes in the sulfhydryl groups in membrane proteins. This protective effect on sperm function was more pronounced with 1 mM of GSH than with 5 mM of GSH.

In this study, we evaluated the effects of glutathione (l-gamma-glutamyl-l-cysteinylglycine; GSH) supplementation of the thawing extender on bull semen parameters to compensate for the decrease in GSH content observed during sperm freezing. To address these questions fully, we used a set of functional sperm tests. These included tests of sperm motility assayed by computer-assisted semen analysis, membrane lipid packing disorder, spontaneous acrosome reaction, free radical production [reactive oxygen species (ROS) generation], sperm chromatin condensation, DNA fragmentation by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling and acridine orange staining measured by flow cytometry. Finally, the in vitro penetrability of in vitro matured oocytes and the in vitro production of embryos were evaluated. The main findings emerging from this study were that addition of GSH to the thawing medium resulted in: (i) a higher number of non-capacitated viable spermatozoa; (ii) a reduction in ROS generation; (iii) lower chromatin condensation; (iv) lower DNA fragmentation; (v) higher oocyte penetration rate in vitro and (vi) higher in vitro embryo production compared with control group. Nevertheless, GSH had no significant effect on motion parameters or the occurrence of the spontaneous acrosome reaction. Addition of GSH to the thawing extender could be of significant benefit in improving the function and fertilizing capacity of frozen bull spermatozoa.

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The acute phase response (APR) is the reaction that occurs in animals in response to disturbances in hemostasis following tissue damage. In horses, the APR is manifested in a variety of pathological processes of various origins, such as infections caused by bacteria, viruses, parasites, arthritis, burns, chemicals, trauma surgery and stress. Acute phase proteins (APPs) are considered those proteins that modify its plasma concentration at least 25% in inflammatory and infectious processes. In adult horses, various respiratory inflammatory processes, gastrointestinal tract, reproductive organs and musculoskeletal system are accompanied by increased levels of a specific APP, so-called serum amyloid type A (SAA). SAA is the most important major APP in the horse. This paper provides a review of physiological factors affecting SAA levels and their role in horses in defense of natural mechanisms, the pathways involved and their material components.

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