Beneficial effects of hypotaurine supplementation in preparation and freezing media on human sperm cryo-capacitation and DNA quality

Abstract

Background Although widely used, slow freezing considerably modifies the functions of human spermatozoa. Cryopreservation induces nuclear sperm alterations and cryo-capacitation, reducing the chances of pregnancy. Hypotaurine is naturally present in the male and female genital tracts and has capacitating, osmolytic and anti-oxidant properties. The analysis were performed on surplus semen of men with normal (n = 19) or abnormal (n = 14) sperm parameters. Spermatozoa were selected by density gradient centrifugation before slow freezing. For each sample, these steps were performed in parallel with (“H+” arm) or without (“H-” arm) hypotaurine supplementation. After thawing, we measured total and progressive mobility, vitality, acrosome integrity, markers of capacitation signaling pathway and nuclear quality. For the latter, we focused on sperm chromatin packaging, DNA fragmentation and the presence of vacuoles in the sperm nucleus. Results Post-thaw spermatozoa selected and frozen in the presence of hypotaurine had a higher vitality (+ 16.7%, p < 0.001), progressive and total motility (+ 39.9% and + 21.6% respectively, p < 0.005) than spermatozoa from the control “H-” arm. Hypotaurine also reduced the non-specific phosphorylation of the capacitation protein markers P110 and P80 (p < 0.01), indicating a decrease in cryo-capacitation. Hypotaurine supplementation reduced chromatin decondensation, measured by chromomycin A3 (− 16.1%, p < 0.05), DNA fragmentation (− 18.7%, p < 0.05) and nuclear vacuolization (− 20.8%, p < 0.05). Conclusion Our study is the first to demonstrate beneficial effects of hypotaurine supplementation in preparation and freezing procedures on human spermatozoa sperm fertilization capacity and nucleus quality. Hypotaurine supplementation limited cryo-capacitation, increased the proportion of live and progressively motile spermatozoa and reduces the percentage of spermatozoa showing chromatin decondensation, DNA fragmentation and nuclear vacuolation. Trial registration Clinical Trial, NCT04011813. Registered 19 May 2019 - Retrospectively registered.

Lactobacillus plantarumsecretions may exert a cryoprotective effect on human sperm motility: A prospective in vitro study

“…In addition to the CPA, the arctic sperm cryopreservation medium contains different amino acids that may play several roles such as: (1) antioxidant (e.g., hypotaurine 15,48,49 ), (2) organic osmolytes (e.g., hypotaurine, 15,49 glycine, [50][51][52] L-alanyl-L-glutamine 53 ), and…”

“…(3) anti-capacitant (e.g., hypotaurine 15,49 ). Moreover, this freezing medium is characterized by the presence of a buffer system comprising (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid),…”

Beneficial effect of L‐ Proline supplementation on the quality of human spermatozoa

“…In the last decades, the study of in vitro incubation of spermatozoa with various antioxidants, including melatonin, resveratrol, penicillamine, hydroxytyrosol, vitamin B12, hypotaurine, and curcumin, has been an exciting research subject (Alamo et al, 2019; Hosseinabadi et al, 2020; Karakus et al, 2021; Kedechi et al, 2017; Pariz et al, 2019; Pons‐Rejraji et al, 2021; Uribe et al, 2020). L‐Proline (Proline) is a membrane‐permeable osmoprotectant and antioxidant that protects cells against cryopreservation‐induced damages (Bottrel et al, 2018).…”

Sperm cryopreservation: current status and future developments

“…The fact that cryocapacitation can be prevented by exposing the cells to cholesterol in order to compensate for the excessive cholesterol efflux engendered by cryopreservation, again suggests the involvement of ROS in this process (Rajoriya et al 2020). Finally, an involvement of excess ROS generation in the cryocapacitation phenomenon is strongly suggested by the ability of antioxidants such as reduced glutathione or hypotaurine to counteract this process (Shah et al 2017;Pons-Rejraji et al 2021). Cryocapacitation is therefore a disruptive, nonphysiological process that reflects the internal disorder generated in spermatozoa as a result of cryopreservation as a consequence of both the physical damage induced during freezing and the initiation of excessive ROS generation as these cells are returned to ambient temperature.…”

“…A wide range of antioxidants have been used in this context, attacking several different stages of the oxidative process. Examples of antioxidants employed for this purpose for the preservation of human semen include curcumin (Riahi et al 2021), L-proline (Moradi et al 2022), hypotaurine (Pons-Rejraji et al 2021), cerium oxide nanoparticles (Hosseinmardi et al 2022), quercetin (Cheraghi et al 2021), plant extracts (Ros-Santaella and Pintus 2021), lipoic acid (Shaygannia et al 2020), L-carnitine and co-enzyme Q10 (Chavoshi Nezhad et al 2021), the combination of L-α-phosphatidylcholine (PC) and L-acetyl-carnitine (Sicchieri et al 2021), sulphoraphane (Valipour et al 2021), vitamin B12 (Hosseinabadi et al 2020) and polyphenols of various kinds including chlorogenic acid (Noto et al 2021), green tea extract (Alqawasmeh et al 2021), resveratrol (Li et al 2018) and myoinositol (Abdolsamadi et al 2020). In animal C Reproduction, Fertility and Development models, additional antioxidants have been assessed in this context but, as far as the authors are aware, have not yet been evaluated for the cryopreservation of human spermatozoa; these reagents include fullerene (Turk et al 2022), Mito-TEMPO (Esmaeilkhanian et al 2021) and idebenone (Lone et al 2019).…”