Lipid peroxidation (a) The lipid peroxidation cascade explained in three stages, called initiation, propagation, and termination. (4-hydroxynonenal (4HNE), malondialdehyde (MDA), and acrolein (ACR)) (b) Lipid peroxidation causes a generation of various electrophilic lipid aldehydes like ACR, 4HNE and MDA. Those electrophiles reduce the function of spermatozoa and do cause even more generation of ROS.