Published-Ahead-of-Print May 25, 2006, DOI:10.2164/jandrol.106.000489
Journal of Andrology, Vol. 27, No. 5, September/October 2006
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.106.000489
Functional Significance of the Sperm Head Morphometric Size and Shape for Determining Freezability in Iberian Red Deer (Cervus elaphus hispanicus) Epididymal Sperm Samples
MILAGROS C. ESTESO*,
,
ANA J. SOLER*,
MARÍA R. FERNÁNDEZ-SANTOS*,
ARMANDO A. QUINTERO-MORENO
AND
JOSE J. GARDE*,
From the * Biology of Reproduction Group,
Department of Game Resources (IDR), Castilla-La Mancha University (UCLM),
Albacete, Spain; the
National Wildlife
Research Institute (IREC), UCLM-CSIC-JCCM, Albacete, Spain; and the
Animal Production Research Unit, Faculty of
Veterinary Medicine, Zulia University, Maracaibo, Venezuela.
|
Correspondence to: Dr José Julián Garde, IDR, Sección de
Recursos Cinegéticos y Ganaderos (IDR), Campus Universitario, 02071,
Albacete, Spain (e-mail:
Julian.Garde{at}uclm.es). |
In the present study, computer-automated sperm head morphometry of
epididymal samples was used to determine if sperm head area and shape are
useful measurements for separating "good" and "bad"
Iberian red deer freezers. A microscope slide was prepared from single diluted
sperm fresh samples collected from 38 mature stags. Slides were air-dried and
stained with Hemacolor. The sperm head area and shape (length/width) for a
minimum of 145 sperm heads were determined for each male by means of the
Sperm-Class Analyser. The remainder of each sample was frozen. After thawing,
sperm cryosurvival was judged in vitro by microscopic assessments of
individual sperm motility and of plasma membrane and acrosome integrities. All
sperm parameters evaluated at thawing were placed in a statistical database
and a multivariate cluster analysis performed. Mean sperm parameters of the 2
clusters generated ("bad" and "good" freezers) were
compared by ANOVA. Our results show that sperm quality at thawing for all
sperm parameters evaluated was significantly higher (P < .01) for
"good" freezers than for the "bad" ones (sperm
motility index: 67.4±2.0 vs 57.1±2.8; NAR: 67.1±2.5 vs
54.5±3.5; viability: 68.8±2.0 vs 60.1±2.8; HOST:
71.3±2.2 vs 63.1±3.1). Additionally, differences (P < .01) in
epididymal sperm head area and shape were found between "good" and
"bad" freezers before freezing, with the smallest overall sperm
head dimensions found in the "good" freezers group (area: 32.04
µm2 vs 34.42 µm2). Thus, the lower the sperm head
area in the fresh samples, the greater the sperm cryoresistance. Our results
show that the 2 groups of males also differ in sperm head shape in fresh
samples (good: 1.96 vs poor: 1.72; P < .01). It is possible that
sperm head area and shape influence total sperm volume, thus causing
differences in heat exchange as well as in movements of water, ions, and
cryoprotectants and, in turn, on sperm freezability.
Key words: cryopreservation, morphology, postmortem recovery
Copyright © 2006 by The American Society of Andrology.