TY - JOUR
T1 - Sensitivity of domestic cat (Felis catus) sperm from normospermic versus teratospermic donors to cold-induced acrosomal damage
AU - Pukazhenthi, Budhan
AU - Pelican, Katharine
AU - Wildt, David
AU - Howard, JoGayle
PY - 1999
Y1 - 1999
N2 - Freeze-thawing cat sperm in cryoprotectant results in extensive membrane damage. To determine whether cooling alone influences sperm structure and viability, we compared the effect of cooling rate on sperm from normospermic (N; > 60% normal sperm per ejaculate) and teratospermic (T; < 40% normal sperm per ejaculate) domestic cats. Electroejaculates were divided into raw or washed (Ham's F-10 + 5% fetal calf serum) aliquots, with the latter resuspended in Ham's F-10 medium or Platz Diluent Variant Filtered without glycerol (20% egg yolk, 11% lactose). Aliquots were 1) maintained at 25°C (no cooling; control), 2) cooled to 5°C in a commercial refrigerator for 30 min (rapid cooling; ~4°C/min), 3) placed in an ice slush at 0°C for 10 min (ultrarapid cooling; ~14°C/min), or 4) cooled to 0°C at 0.5°C/min in a programmable alcohol bath (slow cooling); and aliquots were removed every 4°C. All samples then were warmed to 25°C and evaluated for percentage sperm motility and the proportion of intact acrosomes using a fluorescein- conjugated peanut agglutinin stain. In both cat populations, sperm percentage motility remained unaffected (p > 0.05) immediately after exposure to low temperatures and after warming to 25°C. However, the proportion of spermatozoa with intact acrosomes declined (p < 0.05) after rapid cooling (~4°C/min) to 5°C (N, 65.6%; T, 27.5%) or ultrarapid cooling (~14°C/min) to 0°C (N, 62.1%; T, 23.0%) in comparison to the control value (N, 81.5%; T, 77.5%). Transmission electron microscopy of cooled sperm revealed extensive damage to acrosomal membranes. In contrast, slow cooling (0.5°C/min) to 5°C maintained (p > 0.05) a high proportion of spermatozoa with intact acrosomes (N, 75.5%; T, 68.3%), which also remained similar (p > 0.05) between cat populations (N, 64.7%; T, 56.8%) through continued cooling to 0°C. Results demonstrate that 1) rapid cooling of domestic cat sperm induces significant acrosomal damage without altering sperm motility, 2) spermatozoa from teratospermic males are more susceptible to cold-induced acrosomal damage than normospermic counterparts, and 3) reducing the rate of initial cooling markedly decreases sperm structural damage.
AB - Freeze-thawing cat sperm in cryoprotectant results in extensive membrane damage. To determine whether cooling alone influences sperm structure and viability, we compared the effect of cooling rate on sperm from normospermic (N; > 60% normal sperm per ejaculate) and teratospermic (T; < 40% normal sperm per ejaculate) domestic cats. Electroejaculates were divided into raw or washed (Ham's F-10 + 5% fetal calf serum) aliquots, with the latter resuspended in Ham's F-10 medium or Platz Diluent Variant Filtered without glycerol (20% egg yolk, 11% lactose). Aliquots were 1) maintained at 25°C (no cooling; control), 2) cooled to 5°C in a commercial refrigerator for 30 min (rapid cooling; ~4°C/min), 3) placed in an ice slush at 0°C for 10 min (ultrarapid cooling; ~14°C/min), or 4) cooled to 0°C at 0.5°C/min in a programmable alcohol bath (slow cooling); and aliquots were removed every 4°C. All samples then were warmed to 25°C and evaluated for percentage sperm motility and the proportion of intact acrosomes using a fluorescein- conjugated peanut agglutinin stain. In both cat populations, sperm percentage motility remained unaffected (p > 0.05) immediately after exposure to low temperatures and after warming to 25°C. However, the proportion of spermatozoa with intact acrosomes declined (p < 0.05) after rapid cooling (~4°C/min) to 5°C (N, 65.6%; T, 27.5%) or ultrarapid cooling (~14°C/min) to 0°C (N, 62.1%; T, 23.0%) in comparison to the control value (N, 81.5%; T, 77.5%). Transmission electron microscopy of cooled sperm revealed extensive damage to acrosomal membranes. In contrast, slow cooling (0.5°C/min) to 5°C maintained (p > 0.05) a high proportion of spermatozoa with intact acrosomes (N, 75.5%; T, 68.3%), which also remained similar (p > 0.05) between cat populations (N, 64.7%; T, 56.8%) through continued cooling to 0°C. Results demonstrate that 1) rapid cooling of domestic cat sperm induces significant acrosomal damage without altering sperm motility, 2) spermatozoa from teratospermic males are more susceptible to cold-induced acrosomal damage than normospermic counterparts, and 3) reducing the rate of initial cooling markedly decreases sperm structural damage.
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U2 - 10.1095/biolreprod61.1.135
DO - 10.1095/biolreprod61.1.135
M3 - Article
C2 - 10377041
AN - SCOPUS:0032985936
SN - 0006-3363
VL - 61
SP - 135
EP - 141
JO - Biology of reproduction
JF - Biology of reproduction
IS - 1
ER -