Evaluation of Cryo-injury of Sperm Chromatin According to Computer Controlled Rate Freezing Method Part 2
Surachai Dejarkom MD*, Somboon Kunathikom MD*
Affiliation : * Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol, University
Objective : The present study was designed to determine the effect of the freeze-thawing procedure, computer
controlled rate freezing and duration for six months, on human sperm chromatin (assessed by acridine orange
test), vitality, motility, and morphology.
Design : Experimental study
Materials and Methods : Twenty semen samples were obtained from patients attending the infertility unit. The
semen analysis was measured according to WHO criteria. Sperm morphology was evaluated by strict Kruger
criteria and sperm chromatin were detected by acridine orange test. After semen analysis, each sample was
mixed with cryoprotectant and divided into straw. The straw was frozen with computer controlled rate freezing
method. After 6 months of cryostorage, semen samples were thawed and then the semen was analyed, and
sperm chromatin and morphology were determined.
Results : After six months of cryostorage, the mean percentage of normal sperm chromatin decreased signifi-
cantly (87.3 + 9.0 vs. 51.9 + 27.4, p < 0.001). Vitality, motility, and normal morphology of sperm decreased
significantly (78.7 + 1.9 vs. 32.8 + 10.8, 52.6 + 1.9 vs. 24.1 + 10.9 and 21.4 + 4.3 vs. 18.0 + 4.4 respectively,
p < 0.001).
Conclusions : The computer controlled rate freezing of sperm for six months and thawing process significantly
decreased normal sperm chromatin, vitality, motility, and normal morphology.
Keywords : Cryopreservation, Sperm chromatin integrity, Computer program freezer
