Freezing response and optimal cooling rates for cryopreserving sperm cells of striped bass, Morone saxatilis.
This study explored the optimization of techniques for sperm cryopreservation of an economically important fish species, the striped bass Morone saxatilis. The volumetric shrinkage or the water transport response during freezing of sperm cells was obtained using a differential scanning calorimeter (DSC) technique. Water transport was obtained in the presence of extracellular ice at a cooling rate of 20 degrees C/min in two different media: (1) without cryoprotective agents (CPAs), and (2) with 5% (v/v) dimethyl sulfoxide (DMSO). The sperm cell was modeled as a cylinder of length of 22.8 microm and diameter 0.288 microm and was assumed to have an osmotically inactive cell volume (V(b)) of 0.6 V(0), where V(0) is the isotonic or initial cell volume. By fitting a model of water transport to the experimentally determined water transport data, the best fit membrane permeability parameters (reference membrane permeability to water, L(pg) or L(pg)[cpa] and the activation energy, E(Lp) or E(Lp)[cpa]) were determined and ranged from L(pg)=0.011-0.001 microm/min-atm, and E(Lp)=40.2-9.2 kcal/mol). The parameters obtained in this study suggested that the optimal rate of cooling for striped bass sperm cells in the presence and absence of DMSO range from 14 to 20 degrees C/min. These theoretically predicted rates of optimally freezing M. saxatilis sperm compared quite closely with independent and experimentally determined optimal rates of cooling striped bass sperm.
Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA, USA.
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Thirumala
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Campbell
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Vicknair
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Tiersch
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Devireddy
D000818:Animals; D001492:Bass / Q000502:physiology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D048429:Cell Size; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005615:Freezing; D008297:Male; D009997:Osmotic Pressure; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors
D003451:Cryoprotective Agents; D004121:Dimethyl Sulfoxide