PURPOSE: to compare the characteristics of human semen preserved at +4ºC and at -196ºC for 24 h and to determine which technique is indicated for use in specific procedures. METHODS: semen samples of 24 voluntaries were analyzed after collection and divided into two aliquots, one of them cooled (+4ºC) and the other frozen (-196ºC). Samples were kept at low temperatures for 24 h and then at room temperature for 30 minutes (T1), capacitated (T2) and kept at +37ºC for 90 minutes (T3), being analyzed regarding count and progressive motility at T1, T2 and T3. The General Linear Model was used to analyze results obtained with different techniques, while Wilcoxon's test was used to compare results obtained in two different moments using the same technique (a = 5% e p<0,05). RESULTS: data were missed in one fresh semen sample, in one sample after preservation, in five samples after capacitation and in two samples after incubation. The average number of total motile sperm/mL (NTMS) in fresh semen was 39.7 million (1.3-104.0). After preservation, the average NTMS in cooled semen was 9.6 million (0-37.4) and in frozen semen 8.7 million (0-41.2). After capacitation, the average NTMS was 5.4 million either in cooled (0-21.7), or in frozen semen (0-28). After incubation, the average NTMS in cooled semen was 9.8 million (0-40.5) and in frozen 4.4 million (0-25.6). Concerning count, progressive motility and NTMS, there was no significant difference (p>0,05) between techniques in the three moments of observation. In cooled samples, there was no difference between variables after capacitation and after incubation, but, in frozen semen, count was significantly greater after capacitation. CONCLUSIONS: although there has been no significant difference between semen count and progressive motility in both techniques, the use of cooled semen is recommended for specific procedures within a short time period due to its simplicity and low cost. When frozen semen is necessary, we recommend its use soon after capacitation in order to avoid loss in quality.
Human sperm; Infertility; Spermatozoa Capacitation
