Effect of extracellular adenosine 5'-triphosphate on cryopreserved epididymal cat sperm intracellular ATP concentration, sperm quality, and in vitro fertilizing ability

摘要

Intracellular adenosine 5'-triphosphate (ATP) is essential for supporting sperm function in the fertilization process. During cryopreservation, damage of sperm mitochondria] membrane usually leads to compromised production of intracellular ATP. Recently, extracellular ATP (ATPe) was introduced as a potent activator of sperm motility and fertilizing ability. This study aimed to evaluate (1) levels of intracellular ATP in frozen-thawed epididymal cat sperm after incubation with ATPe and (2) effects of ATPe on epididymal cat sperm parameters after freezing and thawing. Eighteen male cats were included. For each replicate, epididymal sperm from two cats were pooled to one sample (N = 9). Each pooled sample was cryopreserved with the Tris-egg yolk extender into three straws. After thawing, the first and second straws were incubated with 0-, 1.0-, or 2.5-mM ATPe for 10 minutes and evaluated for sperm quality at 10 minutes, 1, 3, and 6 hours after thawing and fertilizing ability. The third straw was evaluated for intracellular ATP concentration in control and with 2.5-mM ATPe treatment. Higher concentration of intracellular sperm ATP was observed in the samples treated with 2.5-mM ATPe compared to the controls (0339 +/- 0.06 mu g/2 x 10(6) sperm vs. 0.002 +/- 0.003 mu g/2 x 10(6) sperm, P = 0.05). In addition, incubation with 2.5-mM ATPe for 10 minutes promoted sperm motility (56.7 +/- 5.0 vs. 533 +/- 4.4%, P = 0.05) and progressive motility (3.1 +/- 0.2 vs. 2.8 +/- 0.4, P = 0.05), mitochondria] membrane potential (36.4 +/- 5.5 vs. 28.7 +/- 4.8%, P = 0.05), and blastocyst rate (36.1 +/- 7.0 and 28.8 +/- 7.4%, P = 0.05) compared with the controls. In contrast, ATPe remarkably interfered acrosome integrity after 6 hours of postthawed incubation. In sum, the present finding that optima] incubation time of postthaw epididymal cat sperm under proper ATPe condition might constitute a rationale for the studies on other endangered wild fads regarding sperm quality and embryo development. (C) 2015 Elsevier Inc. All rights reserved.