DNA methylation in spermatozoa and two generations of offspring after murine spermatogonial stem cell transplantation

BACKGROUND: Apart from its use in research, spermatogonial stem cell transplantation (SSCT) may have important clinical applications. This controlled study aimed at evaluating the safety of SSCT by analysing the DNA methylation pattern of Igf2, Peg1 and ?-Actin both in spermatozoa and live born offspring obtained after SSCT in mice. METHODS: Testicular cell suspensions were transplanted to the testes of genetically sterile WW recipients. Transplanted males were mated with fertile females and their 1st and 2nd generation offspring were examined and compared with controls with respect to weight, length and DNA methylation patterns. Sodium-bisulfite treated genomic DNA extracted from post-transplantation spermatozoa, liver, kidney and placenta of 1st and 2nd generation offspring was PCR-amplified to obtain Igf2, Peg1 and ?-Actin gene fragments. Pyrosequencing was used to individually quantify the resulting artificial C/T sequence variation at CpG sites. RESULTS: First and second generation offspring developed normally with their length and weight not being different from controls. Also the DNA methylation pattern of Igf2, Peg1 and ?-Actin was not different among controls, spermatozoa obtained after SSCT and 1st and 2nd generation offspring. CONCLUSIONS: Spermatogonial stem cell transplantation between syngenic individuals was not associated with changes in foetal development or with differences in DNA methylation pattern of Igf2, Peg1 and ?-Actin in spermatozoa obtained after SSCT and in different tissues of two subsequent generations of offspring obtained after SSCT.