Currentmethods of analyzing spermchromatin competency overlook the inner spermcompartmentwhich is inaccessible to probes\nand reagents. By breaking the molecular protamine disulfide bridges, theDNAtoroids are exposed to integrity analysis.Theaimwas\nto develop a simple nuclear toroid test and determine its association with fertilization, pregnancy, and miscarriage. The approach\ninvolved treating washed sperm remaining after ICSI procedures (N = 35 cases) with acidified Triton X-100 and dithiothreitol\n(DTT) before Diff-Quik staining. Percentages of sperm with normal chromatin indicated by light-colored nuclei were assessed.\nThe toroid integrity test showed more sperm with normal chromatin in the pregnant group (73.6 �± 1.7%, mean �± SEM) when\ncompared with themiscarriage (51.2 �± 6.6%) or nonpregnant groups (60.9 �± 4.8%). Furthermore, the toroid results were correlated\nwith ICSI fertilization (R = 0.32, P = 0.04) and pregnancy outcome (pregnant cases 73.6 �± 1.7% versus nonpregnant 58.0 �± 3.9%,\nP = 0.001). ROCcalculated cut-offwas >70.0% for normal toroid integrity (sensitivity 0.98, specificity 0.33, and diagnostic accuracy\n78.3%). An association between normal sperm toroid integrity and miscarriage was evident when the staining procedure included\nacidified detergent DTT pretreatment.
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