SPERM CHROMATIN ANOMALIES CAN INFLUENCE DECONDENSATION AFTER INTRACYTOPLASMIC SPERM INJECTION

In this study we investigated whether morphology and chromatin anomali es in human spermatozoa can influence fertilization after intracytopla smic sperm injection (ICSI). We examined unfertilized oocytes, using t he fluorochrome Hoechst 33342, to determine whether a relationship exi sts between failure of fertilization and sperm chromatin quality, Sper m chromatin packaging quality was assessed using the chromomycin A(3) (CMA(3)) fluorochrome, and the presence of DNA damage in spermatozoa, using in-situ nick translation, Normal males present sperm parameters with a normal morphology of >20%, CMA(3) fluorescence of <30% and exhi bit endogenous nicks in <10% of their spermatozoa, When patients were separated according to these values no difference was observed in thei r fertilization rates after ICSI, When the unfertilized ICSI oocytes w ere examined, we found that patients with CMA(3) fluorescence of <30% and nicks in <10% of their spermatozoa had only 17.5 and 21.6% respect ively of their unfertilized oocytes containing spermatozoa that remain ed condensed, In contrast, patients with higher CMA(3) and nick values had a significantly higher number, 41.2 and 48.9%, of their unfertili zed oocytes containing condensed spermatozoa. Sperm morphology did not show any such pattern, The percentage of spermatozoa which had initia ted decondensation in unfertilized oocytes was not influenced by morph ology, CMA(3) fluorescence or nicks, In light of these results we post ulate that poor chromatin packaging and/or damaged DNA may contribute to failure of sperm decondensation after ICSI and result in failure of fertilization.