Jr. Correa et Pm. Zavos, THE HYPOOSMOTIC SWELLING TEST - ITS EMPLOYMENT AS AN ASSAY TO EVALUATE THE FUNCTIONAL INTEGRITY OF THE FROZEN-THAWED BOVINE SPERM MEMBRANE, Theriogenology, 42(2), 1994, pp. 351-360
The objective of this study was to determine the effectiveness of the
hypoosmotic swelling (HOS) test together with the supravital test as a
means of evaluating the functional integrity of frozen-thawed bovine
sperm membrane. A solution consisting of equal parts of fructose and s
odium citrate was prepared and the osmolality varied from 50 to 300 mO
sm/L. From these various solutions under study, the 100 mOsm/L solutio
n resulted in a maximal number of clearly identifiable swollen spermat
ozoa. The results from the supravital test indicated that the HOS solu
tion preserved the integrity and prevented excessive lysis of the sper
m membrane during the assay. A good correlation was found between the
percentage of motile spermatozoa and spermatozoa that reacted to the H
OS test (r=0.73) and between the percentage of sperm with intact membr
anes and HOS reactive sperm (r=0.81). Spermatozoa showing swelling of
the entire tail region accounted for more than 60% of the total swelli
ng for the HOS solution at 100 mOsm/L. The results obtained in this st
udy indicate that frozen-thawed bovine spermatozoa did react to the HO
S test. This technique could prove useful in studies involving the fun
ction of the sperm membrane and could possibly predict the sperm's abi
lity to fertilize.