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Comprehensive overview of the toxicities of small-molecule cryoprotectants for carnivorous spermatozoa: foundation
Isaac Karimi1, Layth Jasim Mohammad2, A Suvitha3
1Research Group of Bioengineering and Biotechnology, Laboratory for Computational Physiology, Department of Biology, Faculty of Science, Razi University, Kermanshah, Iran.
Background:
The specific and non-specific toxicities of cryoprotective agents (CPAs) for semen or spermatozoa cryopreservation/vitrification (SC/SV) remain challenges to the success of assisted reproductive technologies.
Objective:
We searched for and integrated the physicochemical and toxicological characteristics of small-molecule CPAs as well as curated the information of all extenders reported for carnivores to provide a foundation for new research avenues and computational cryobiology.
Methods:
The PubMed database was systematically searched for CPAs reported in SC/SV of carnivores from 1964 to 2024. The physicochemical features, ADMET parameters, toxicity classes, optimized structures, biological activities, thermodynamic equilibrium constants, and kinetic parameters were curated and assessed computationally.
Results:
Sixty-two relevant papers pertaining to CPAs used in SC/SV were found, and 11 CPAs were selected. Among the properties of CPAs, the molecular weight range (59-758 g/mol), melting point (-60°C to 236°C), XlogP3 (-4.5 to 12.9), topological polar surface area (TPSA; 20-160 Å2), Caco2 permeability (-0.62 to 1.55 log(Papp) in 10-6 cm/s), volume of distribution (-1.04 to 0.19 log L/kg), unbound fraction of a CPA in plasma (0.198-0.895), and Tetrahymena pyriformis toxicity (log µg/L; -2.230 to 0.285) are reported here. Glutathione, dimethyl formamide, methyl formamide, and dimethyl sulfoxide were used as the P-glycoprotein substrates. Ethylene glycol, dimethyl sulfoxide, dimethyl formamide, methyl formamide, glycerol, and soybean lecithin showed Caco2 permeabilities in this order, whereas fructose, glutathione, glutamine, glucose, and citric acid were not Caco2-permeable. The CPAs were distributed in various compartments and could alter the physiological properties of both seminal plasma and spermatozoa. Low volume distributions of all CPAs except glucose indicate high water solubility or high protein binding because higher amounts of the CPAs remain in the seminal plasma.
Conclusion:
ADMET information of the CPAs and extenders in the bipartite compartments of seminal plasma and intracellular spaces of spermatozoa are very important for systematic definition and integration because the nature of the extenders and seminal plasma could alter the physiology of cryopreserved spermatozoa.
Insights
Cryoprotective agents (CPAs) used in semen cryopreservation have challenges. This study analyzes CPA properties to improve assisted reproductive technologies and computational cryobiology for carnivores.
Area of Science:
- Veterinary Science
- Reproductive Biology
- Computational Biology
Background:
- Cryopreservation of semen and spermatozoa (SC/SV) faces challenges due to the specific and non-specific toxicities of cryoprotective agents (CPAs).
- Understanding CPA properties is crucial for advancing assisted reproductive technologies.
Purpose of the Study:
- To integrate physicochemical and toxicological data of small-molecule CPAs for carnivore SC/SV.
- To establish a foundation for novel research and computational cryobiology in this field.
Main Methods:
- Systematic search of the PubMed database for CPAs in carnivore SC/SV (1964-2024).
- Computational assessment of physicochemical features, ADMET parameters, toxicity, and kinetic/thermodynamic properties of selected CPAs.
Main Results:
- Eleven CPAs were selected from 62 relevant papers, with diverse properties including molecular weight, melting point, lipophilicity (XlogP3), and polar surface area (TPSA).
- Permeability studies (Caco2) identified differential penetration of CPAs, with some (e.g., ethylene glycol, DMSO) being permeable and others (e.g., fructose, glucose) not.
- Volume of distribution data suggests most CPAs have high water solubility or protein binding, remaining primarily in the seminal plasma.
Conclusions:
- ADMET information for CPAs and extenders is vital for understanding their effects in seminal plasma and spermatozoa.
- The interaction of CPAs with seminal plasma and intracellular spaces significantly impacts the physiology of cryopreserved spermatozoa.
