Change of the Level of A Caspase-3 Activity During the Early Ontogenesis Leads to The Impairment of Memory and Learning in Adult Rats

The delayed time effect of impairing the learning and memorization ability in rats after changing the level of caspase-3 activity during the early postnatal ontogenesis was discovered for the first time. As the result of intraventricular injection of the caspase inhibitor (Ac-DEVD-CHO) into the brain of 20-day-old infant rats the impairments of memory and learning were observed both during the abnormally increased activity of the caspase-3 on the 7th day after the injection and in 30-45 days after the injection, when the level of the activity of this enzyme corresponded to an age norm. The analogous results were obtained in young and adult rats that had been exposed to the prenatal hypoxia (7% of oxygen within 3 hours on the 14th day of their birth - E14). However, it was found that the stronger and longer increase of the caspase-3 activity after the prenatal hypoxia was accompanied with more crucial impairment of memory and learning in the rats during their testing in a two-level 8-arm radial maze. The revealed positive correlation between the level of changing the caspase activity during the early ontogenesis and the disruption of the cognitive functions in adult rats shows that it is necessary to keep the optimal level of the caspase-3 activity within the early stages for providing the normal brain and behavior development in the process of their maturation. It was observed that the treatments by Ac-DEVD-CHO provoke significant cognitive impairment in adults without any cell death in early ontogenesis, suggesting some non-apoptitic mechanisms to be involved.