Cryo letters最新文献

Background: Film boiling occurs in the cooling process of samples with liquid nitrogen, which limits heat transfer and decreases the cooling rate.

Objective and methods: The study developed a method to enhance convective heat transfer by wrapping the French straw (FS) with a layer of medical gauze upon cooling to eliminate film boiling. A numerical model was used to study the thermodynamic mechanism in the method.

Results: Numerical simulation based on heat transfer and crystallization equations indicated that wrapping the FS with medical gauze could suppress film boiling. Experimental verification showed the increased cooling rate and better cell survival when wrapped FS was used.

Conclusion: Numerical simulation and experimental verification demonstrated the efficacy of wrapping FS with medical gauze for better cell cryopreservation. Doi.org/10.54680/fr23510110312.

The loss of biodiversity caused by anthropogenic actions is also a reality for the members of the Felidae family. Except for the domestic cat, all felid species have some degree of threat of extinction in their natural habitat. For this reason, felids have been included in conservation-related studies. This scenario has aroused increasing interest in the formation of somatic cell banks, which when efficiently implemented can be used in preservation strategies for the species. Nevertheless, one of the important steps in the formation of these banks is the understanding of the technical principles and variations involved in cryopreservation techniques, especially because cryopreservation increases the possibilities for Assisted Reproduction Technologies (ARTs) by making the use of biological materials independent of time and space. In wild felids, several species already have promising results in the formation of somatic cell banks, and studies aimed at better viability rates have been constantly proposed, as well as new species have been studied. In some species, aspects involved in successful cryopreservation are already well defined, and slow freezing associated with cryoprotectant solutions composed of intra- and extracellular substances is the most useful approach. The aim of this review was to present the main parameters involved in the elaboration of a somatic cell cryopreservation protocol and their effects, as well as to address the main results achieved for different wild felids. Doi.org/10.54680/fr23510110112.

Background: The use of sulfated polysaccharides (PS) in seminal cooling is known to improve seminal quality.

Objective: To evaluate the effect of different concentrations of PS, extracted from the macroalgae Gracilaria domigensis as a supplement to the seminal cooling medium of the reophilic fish Prochilodus brevis (common curimatã).

Materials and methods: Five semen pools were diluted in ACP-104 (treatment T1), in BTS® (T2) and in BTS® with different concentrations of PS (0.5 [T3]; 1.0 [T4] and 1.5 [T5]). The samples were cooled for different times (0, 6, 24, 48, 72, 96 and 120 h) and after each hour they were analyzed for: morphology, membrane integrity, DNA integrity and sperm kinetics.

Results: There were no significant differences between the treatments containing different concentrations of sulfated polysaccharides. Regarding the different cooling times, it was possible to observe that after hour 96, there was a reduction in the parameters of sperm kinetics. For DNA integrity there was no significant difference in relation to the treatments nor in relation to the hours. For membrane integrity, a reduction was noted as of hour 96, but there was no influence of polysaccharides. For the sperm morphology, there was no statistical difference between the hours, however the BTS was better than the ACP-104.

Conclusion: It is concluded that the use of polysaccharides in seminal cooling has no negative effect on sperm parameters and proves that seminal cooling keeps the material viable for up to 72 hours. Doi: 10.54680/fr23410110512.

Background: Glycerol is a cryoprotectant widely used in the freezing of mammalian semen, but no study has demonstrated its optimum concentration and the appropriate exposure time for equine species.

Objective: To demonstrate that the exposure time (15, 30, 45, 60, 75 and 90 min) versus concentration (2, 3, 4 and 5%) of the cryoprotectant glycerol influences the freezing success of equine semen.

Materials and methods: The ejaculate of 12 stallions were frozen in different glycerol concentrations following different exposure times. The thawed sperm was evaluated for kinetic parameters using a Computer Assisted Semen Analysis (CASA) system and cell feature parameters were assessed by flow cytometry.

Results: Considering the total and progressive motility of the spermatozoa, we concluded that protocols using 5% glycerol for 15 and 30 min exposure, 4% glycerol for 45 min exposure and 3% glycerol for 90 min exposure generated the best results.

Conclusion: We suggest the use of any of these protocols for a better cryopreservation of equine semen. Doi: 10.54680/fr23410110412.

Background: Increased cooling and warming rates by using a suitable cryodevice allows the use of lower cryoprotectant concentration and reduces cryoinjuries as a result of the rapid passage through the 'dangerous' temperature zone.

Objective: To evaluate the effectiveness of newly customized strip pulled straw (SPS) with respect to post warming quality, viability, and in vitro maturation for immature oocytes post-vitrification of.

Materials and methods: SPS was prepared using conventional French mini straw to combine the merits of OPS and the Cryotop system. Immature sheep oocytes were treated in 15% EG + 15% DMSO, loaded on SPS and plunged into liquid nitrogen (LN). Post thaw quality, viability, and maturation rates of oocytes were determined after 1 week storage in LN.

Results: SPS achieved a post-thaw morphological survival of 90.9% with 9.0% morphological defects, 96.4% viability and 51% in vitro maturation. In comparison to OPS, SPS had higher post thaw survival (86.5% vs 67.9%) and maturation rate (57.7% vs 50.5%) with lower morphological defects (13.5% vs 32.1%). Cumulus cell loss was the highest among morphological abnormalities of post warm oocytes in SPS (40.9%) and OPS (44.1%). The data showed acceptable post thaw survival, viability and in vitro maturation rate of immature ovine oocytes using SPS as compared to traditional OPS.

Conclusion: SPS can be used as a cost effective alternative device for oocyte vitrification. Doi: 10.54680/fr23410110212.