In the studies on the hatching mechanisms in mammals, many investigators focused on the embryonic intrinsic factor(s) in in vitro culture, but the uterine environment as the extrinsic factor(s) is thought to play an important role in hatching mechanism. Therefore, to evaluate the effect of uterine environment on the hatching event in vivo, the immature(GV) and ovulated(MII) oocytes, and the late 2-cell embryos of mouse were transferred to pseudopregnant foster mother's uterus during peri-implantation period. So it was verified whether there would happen hatching by only uterine environment independently on embryonic stage. The ultrastructural changes of the zona surface of transferred group were compared with those of in vivo and vitro group by SEM. 36 hrs after transfer, the immature and ovulated oocytes almost degenerated, and the late 2-cell embryos developed to various embryonic stages. However, the embryos which didn't develop to blastula stage did not hatch. The ultrastructural network of ZP in transferred group seemed to be smoothed uniformly, which was different from in vitro group. In conclusion, it is suggested that the uterine environment during peri-implantation period enhances the embryo hatching by provoking the structural change of ZP.
Animals ; Blastula ; Embryonic Structures* ; Herpes Zoster* ; Humans ; Mammals ; Mice* ; Oocytes* ; Research Personnel ; Uterus ; Zona Pellucida*

AIMTo detect the expression of hepatitis B virus (HBV) genes (HB S and C genes) in early embryonic cells after introducing motile human sperm carrying HBV DNA into zona-free hamster oocytes via the in vitro fertilization (IVF) technique.

METHODSHuman sperm-mediated HBV genes were delivered into zona-free hamster oocytes by the IVF method. Polymerase chain reaction (PCR) was used to detect HB S and pre-Core/Core (pre-C/C) coding genes both in one- and two-cell embryos. Reverse transcription-PCR (RT-PCR) analysis was used to study the expression of the two genes. Fluorescence in situ hybridization (FISH) analysis using the full-length HBV DNA as the hybridization probe was performed to confirm the integration of viral DNA in the host embryonic genome.

RESULTSBoth HB S and pre-C/C coding genes are present and transcribed in one- and two-cell embryos originated from hamster ova IVF with human spermatozoa carrying HBV DNA sequences.

CONCLUSIONSperm-mediated HBV genes are able to replicate and express themselves in early embryonic cells. These results provide direct evidence that HBV DNA could transmit vertically to the next generation via the male germ line.

Animals ; Blastula ; virology ; Cricetinae ; DNA Primers ; Female ; Fertilization in Vitro ; Gene Expression Regulation, Viral ; Genome, Viral ; Hepatitis B virus ; genetics ; Humans ; Male ; Mesocricetus ; Oocytes ; physiology ; Ovum ; virology ; Polymerase Chain Reaction ; Semen ; virology ; Spermatozoa ; virology ; Transfection ; Virus Replication ; Zona Pellucida ; physiology