Cryo letters最新文献

Cryopreservation has been used over many decades for the maintenance of viable biological specimens. Its expansion into the area of fertility preservation has been a natural outcome of the increased risks to human fertility from diseases, such as cancer and its treatment protocols, including radiation and chemo-therapy, and the general lifestyle trend to later marriages. The use of assisted reproductive techniques (ART) in preserving fertility have benefitted significantly from new scientific approaches, such as cryostorage, in which live cells and tissues are stored at low temperatures and revived when necessary. This review focuses on "cryopreservation science monitoring in reproductive biomedicine" to evaluate knowledge, trends, driving forces, impetus, and emerging technologies in order to draw a future roadmap for this field. Our analysis of the field of cryobiology emphasizes the significance of strategic planning of cryobiology research to support more its extensive use in therapeutics in the future. The Royan Institute (Tehran, Iran) recognises this need and has developed a strategic plan to engage in multidisciplinary research on the application of cryobiology, including cryobioengineering, in disease mitigation. We hoped that this study can help improve the quality and quantity of public discourse and expert awareness of the role for cryopreservation in fertility preservation within ART. DOI: 10.54680/fr23410110112.

Background: Persian walnut (Juglans regia L.) is one of the most economically important nut crops. In the Western Tien Shan in Kazakhstan, walnut forests are the northernmost in the natural range of this species. Shoot tip cryopreservation is an important strategy to ensure long-term clonal conservation of plant genetic resources.

Objective: To determine the effect of cold acclimation duration (0-6 weeks) with alternating temperatures (8 h at 22 degree C, light intensity 10 μmol m^-2 s^-1/16 h at -1 degree C, in the dark) and of plant vitrification solution 2 (PVS2) exposure duration (30, 50, 80 or 100 min) on shoot tip regrowth after cryopreservation by vitrification.

Materials and methods: In vitro-grown shoots of three wild Juglans regia accessions from a native population of Sairam-Ugam National Natural Park in the south of Kazakhstan and of cultivar Milotai 10 were used as sources of plant material. Shoot tips (1.8-2.0 mm with five to six leaf primordia) were excised from in vitro-grown shoots and cryopreserved using PVS2 vitrification technique.

Results: Regrowth of cryopreserved shoot tips increased and was significantly higher (P < 0.05) after 4-6 weeks cold acclimation with the highest regrowth between 59.9-67.8 degree after 5 weeks for the four genotypes tested. The highest regrowth level was obtained after 80 min of PVS2 exposure, which was significantly better (P < 0.05) compared to 30, 50 or 100 min exposure.

Conclusion: The PVS2 vitrification protocol established is very effective for cryopreservation of both unique wild J. regia germplasm and of walnut cultivars. Doi: 10.54680/fr23410110612.

Backgrund: Goldfish Carassius auratus is a popular ornamental fish extensively cultured worldwide. Sperm cryopreservation is a common fish breeding method that ensures sperm availability around the year. Studies on cryopreservation of goldfish sperm, especially on the suitability of cryoprotectant types and pre-freezing time, are scarcely available.

Objective: To determine the most suitable type of cryoprotectant and pre-freezing for the successful cryopreservation of goldfish sperm.

Materials and methods: A completely randomized design with two factors was utilized in this study. The first factor is the type of cryoprotectants, which included methanol, ethanol, ethylene glycol, glycerol, and DMSO. The second is pre-freezing times of 10, 20, 30, and 40 min at each of the pre-freezing temperatures of 4 degree C, -10 degree C, and -79 degree C, meaning that the total times for the ramping down of temperature were 30, 60, 90 and 120 min, respectively. The Ringer solution and 10% egg yolk were used as extender and extracellular cryoprotectant. The sperm was stored at -179 degree C for 7 days.

Results: The ANOVA test showed that cryoprotectants and pre-freezing significantly affected the motility, viability, and fertility of goldfish sperm after freezing in liquid nitrogen for 7 days (P<0.05). Furthermore, 10% DMSO combined with 15% egg yolk with an pre-freezing time of 20 min can maintain sperm motility, viability, and fertility higher than other treatments, by 79%, 80%, and 33%, respectively. The agarose gel electrophoresis showed no DNA fragmentation in all samples, including fresh sperm.

Conclusion: We conclude that 10% DMSO combined with 15% egg yolk and 20 min pre-freezing is the best treatment for goldfish sperm cryopreservation. DOI: 10.54680/fr23310110412.

Background: Indian Wild Orange (Citrus indica Tanaka) is an endangered and endemic species from northeast India for which effective ex situ conservation strategies, including embryo cryopreservation, are urgently needed.

Materials and methods: Desiccation tolerance and cryopreservation ability for embryonic axes of Citrus indica was determined using three techniques (air desiccation-freezing, PVS2 vitrification-freezing and encapsulation-dehydration-freezing). Success was assessed as survival and recovery in vitro.

Results: Successful cryopreservation of embryonic axes was achieved using all three methods, with the highest survival achieved when using air desiccation-freezing (90%) followed by encapsulation-dehydration (85%) and PVS2 vitrification cryopreservation (80%). Regeneration levels were lower than survival levels for all three proceedures. Post-cryo regeneration success was: encapsulation-dehydration (64%) > air desiccation-freezing (55%) > PVS2 vitrification (52%).

Conclusion: Although there was relatively high post-cryopreservation recovery growth obtained using all the three techniques, the air desiccation-freezing technique is preferred, as it is a simple, practical and reproducible technique for the long-term cryobanking of this important wild species. Doi: 10.54680/fr23310110512.

Background: Vitrification of embryos has become the basic means of assisted reproductive technology (ART) therapy in recent years. Concerns have also been raised about the safety of vitrification and the effect of cryopreservation time. Most of the previous studies were on the data within 6 years of cryopreservation.

Objective: In this study, we aimed to evaluate the impact of long-term cryopreservation (>6 years) on pregnancy and neonatal outcomes.

Materials and methods: This research was a single-center, retrospective analysis, including 426 frozen-thawed embryo transfer (FET) cycles. Patients who participated in IVF-FET cycles between January 2013 to December 2020 were analyzed. Preferentially matched participants were divided into three groups according to storage time: group A (>72 months), group B (0-3 months, propensity score matching [PSM] according to the age of oocyte retrieval), and group C (0-3 months, PSM according to the age of embryo transfer).

Results: Our results revealed that there were no significant differences in human chorionic gonadotropin [HCG] positive rate, clinical pregnancy rate, miscarriage rate, live birth rate, and neonatal outcomes when the embryo storage duration >72 months. But the proportion of high birth weight was higher in group A (>72 months) when matched according to age at embryo transfer.

Conclusion: The results of our study showed that long-term cryopreservation had no effect on the pregnancy and neonatal outcomes of vitrification. The results offer evidence for the safety of using long-term cryopreservation embryos after vitrification. DOI: 10.54680/fr23310110612.