Integridade de DNA espermático de carneiros morada nova submetidos à insulação escrotal

Abstract

The testicular thermal elevation induces a faulty protamination of the spermatic DNA and consequently a DNA fragmentation, such damageis not identified by conventional spermogram. Thus, techniques such as SCD test (Sperm Chromatin Dispersion Test) are used in laboratories to detect the DNA fragmentation and scrotal insulation as experimental methods regarding testicular thermal elevation. In this paper, six rams Morada Nova underwent scrotal insulation, reaching testicular temperature levels of 38.2 ° C. The Semen was collected by electroejaculation weekly for 141 days. Each sample was analyzed through conventional spermogram parameters and through the SCD test. The SCD test identifies the intact sperm cells (which showed halo) and sperm cells with DNA fragmentation (no halo). In the experiment, there was a decrease in DNA integrity between the pre-insulation period and day 7 and between the pre-insulation period and day 11. The DNA fragmentation reached its highest point on day 28, once that this period had a 0% average halo appearance. During the critical period, with the lowest average halo appearance, there was no statistical difference and average values ranged from 0 to 18.53%. Coincidentally to the critical period, it was noted that during this period there was no motility, however, the early recovery of motility occurred from day 42, even before the recovery of damage done to DNA. The DNA fragmentation begins to decrease from day 77 and this fragmentation decreases progressively. From the pre-insulation period to day 120 no statistical difference were shown, therefore proving that the damage caused by insulation in the spermatic DNA is a temporary and reversible fact.