Relationship between nuclear chromatin decondensation (NCD) in vitro and other sperm parameters and their predictive value on fertilization rate in IVF program

Abstract

The purpose of this study was to determine the in-vitro induced nuclear chromatin decondensation (NCD) of human spermatozoa and its value in combination with routine semen analysis in predicting the outcome of in-vitro fertilization (IVF). The ejaculate of 52 couples, undergoing IVF, was incubated with lithium diidosalicylic acid (LIS) and dithiothreitol (DTT) (G.1) or with heparin and sodium dodecyl sulphate (SDS) (G.2) to induce chromatin decondensation (NCD). Smears were made at 30, 60, and 120 min after incubation. NCD was evaluated by morphometrical detection of the surface area of the spermatozoa using a semiautomatic image analysis system (IBAS). In both groups, the sperm heads showed a significant enlargement after 30, 60, and 120 min incubation in comparison to the initial size. However, no correlation was found between NCD at various periods of time and the fertilization rates. The mean area of the sperm heads in the native sample in the G.1 was 9.45+/- 1.33 microm(2) and 9.02+/- 1.15 microm(2) in the G.2. This area increased after incubation for 30, 60, and 120 min to 10.92 +/- 1.48, 12.26+/- 2.16, 13.54+/- 3.14, and 15.35+/- 7.78 microm(2) in the first group (G.1) and to 10.29 +/- 1.15, 11.23 +/- 1.85, 11.46 +/- 1.97, and 11.27 +/- 2.82 microm(2) in the second group, respectively. NCD in vitro after incubation with LIS + DTT or heparin + SDS could not be recommended as a predictive parameter for IVF outcome.