Reactive oxygen and nitrogen species functions in reproduction: possible pharmacological tools to treat human infertility

Maturation of sperm into potent, fertile cells, fertilization and embryo development, both in vivo and in in vitro fertilization (IVF) are redox-sensitive processes. Reactive oxygen and nitrogen species (ROS and RNS, respectively) - superoxide anion radical (O2•¦) and nitric oxide (•NO), play an important regulatory role at all fertilization stages; acting as initiators of capacitation and effectors of fertilization. Systems that produce O2•¦ and •NO are specific in the reproductive cells. Their regulation is also specific. There is no new life without O2•¦ and •NO, but the mechanisms of redox regulation in fertilization are elusive. The subject matter of this project is redox dependent regulatory mechanisms in human IVF. This includes O2•¦ and •NO producing systems, location and quantity of their production, and O2•¦ and •NO dependent signaling pathways during sperm maturation and early embryo development. These aspects will be studied in the sperm with different pathologies (oligospermia, teratospermia etc), with the testing of possible improvements of sperm capacitation and fertilization by natural and synthetic modulators of O2•¦ and •NO production. In fragmented preimplantation embryos the focus will be directed to the degree of fragmentation and specificities of blastomeres and fragments. This research should contribute to the knowledge of the mechanisms of redox processes in reproductive biology and to the improvement of IVF by testing pharmacological redox modulators.