This survey examines three different methods to cryopreservate mouse sperm and if there is a significant difference in terms of their effectiveness. For protocol 1 a diluter, especially a CPA solution (18 % raffinose, 3 % skimmed milk), is used. For protocol 2 MTG to the CPA solution is added and for protocol 3 l-glutamine. Therefore, sperm of 15 mice from the strain BALB/cAnNCrl and strain C57BL/6NCrl is used. Per animal, the sperm from one cauda epididymis and from the vas deferens is taken for the fresh sperm suspension, the sperm from the other one is used for the cryopreservation. The motility for the fresh sperm specimen and for the defrosted specimen is estimated and afterwards examined with the CASA-System (SpermVision). Furthermore, the total motility, the progressive forward motion, DCL, DSL, DAP, VCL, VSL, VAP, ALH, BCF, LIN, STR and WOB is evaluated. Additionally, the Viability was determined. The result shows that the amount of the forward moving sperms concerning the estimated motility was significantly lower in protocol 2 than in protocol 1 or 3. Although, the amount of the movable sperms was significantly higher.
It can also be perceived from the values of the CASA examination that the motility, the progressive forward motion and the viability do not significantly deviate. However, concerning the velocity parameters, a divergence was observed. The values of VSL and VAP were significantly lower in protocol 2 than in the other protocols. It can be presumed that glycerol changes the mobility. The tension metrics DSL and DAP showed in protocol 2 a significant scale down. The protection from pathomorphologic degeneration during the freezing process was considerably better in protocol 2 than in the others. It turned out, that sperm from strain B6 reacted better in protocol 2 than sperm from strain BALB/c (Anhang, Figure 10).
The results of the survey show that none of the used protocols exceeds the others. Nevertheless, all of them do have their pros and cons. Besides, some strains react obviously differently to various deep freezing methods. Due to the fact that none of these procedures show optimal results after defrost, it is essential to do further research on this field of study, to preserve the very sensitive mice sperm even better.