The development of cat testicular sperm cryopreservation protocols: Effects of tissue fragments or sperm cell suspension

• In endangered animals that have been found dead or sterilized for medical reasons, testis isthe ultimate source of haploid DNA or sperm. Thus, preservation of testicular sperm maybe performed to rescue their genetics. The aim of this study was to evaluate protocols fortesticular sperm freezing: as tissue fragments or cell suspension in domestic cats as amodel. A pair of testes from each cat (n ¼ 9) were cut into eight equal pieces. Fourrandomly selected pieces were cryopreserved as: (1) tissue pieces using two-step freezing;(2) tissue pieces using a slow passive cooling device (CoolCell); (3) sperm suspension aftersingle-layer centrifugation (SLC) through colloids; and (4) sperm suspension without beingprocessed through SLC. A testicular piece from each cat served as fresh control. Testicularsperm membrane and DNA integrity were evaluated before, and after, the cryopreservationprocess. In addition, spermatogenic cell types (testicular sperm, spermatogonia, spermatocyte,and spermatid) present in the suspension samples were counted before andafter SLC. The results found that testicular sperm membrane integrity in the suspensionafter SLC process was higher than that in the fragment form neither using the two-step norCoolCell freezing, both before and after freezing (before freezing: 92.3 3.4 vs. 81 4.5and 80.0 7.0; after freezing: 84.5 4.6 vs. 71.2 12 and 76.2 4.6; P 0.05). Testicularsperm DNA integrity was, however, not different among groups. Furthermore, the samplesprocessed through the SLC had higher ration of sperm cells: other spermatogenic cells thanthose were not processed through the SLC (88.9 3.8 vs. 30 7.9; P 0.05). In summary,testicular sperm cryopreserved as a minced suspension is considered suitable in terms ofpreventing sperm membrane integrity, and SLC is considered a selection tool for enrichinghaploid sperm cells from castrated or postmortem cats.

Ämnesord

LANTBRUKSVETENSKAPER  -- Veterinärmedicin -- Annan veterinärmedicin (hsv//swe)

AGRICULTURAL SCIENCES  -- Veterinary Science -- Other Veterinary Science (hsv//eng)

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