Nucleolar segregation coincides with nuclear accumulation of death domain in neurons undergoing apoptosis induced by ischemia reperfusion injury
| Authors | |
|---|---|
| Year of publication | 2003 |
| Type | Article in Periodical |
| Magazine / Source | Physiological Research |
| MU Faculty or unit | |
| Citation | |
| Field | Genetics and molecular biology |
| Keywords | apoptosis; caspase-3; nucleoli; MADD |
| Description | We focused on histochemical detection of distribution of NOR (argyrophylic nucleolar proteins) reflecting nucleolar integrity, immunohistochemical detection of MADD (mitogen activated death domain), a protein accumulated in nucleoli upon stimulation by ischemia and active form of caspase-3, a universal proteolytic enzyme of apoptosis. The terminal deoxynucleotidyl- transferase (TdT)-mediated dUTP-biotin nick-end-labeling method (TUNEL) proved the presence of in situ DNA fragmentation. We used the model of transient focal cerebral ischemia in rats. The period of ischemia lasted 15, 30, 60 and 120 minutes followed by 48 hrs of reperfusion. We examined the frontal lobe of the ipsilateral hemisphere. We found disintegrated nucleoli in all investigated periods of ischemia in cortical as well as subcortical neurons whereas the neurons of intact animals showed compact nucleoli with a few satellites. Nuclear positivity for MADD was apparent after 15 min. in neocortex and peaked after 30 min. of ischemia. On the other hand, the subcortical neurons showed nuclear positivity for MADD after 60 and 120 minutes. The intact brain tissue showed negative nuclei with only a slight cytoplasmic staining. The immunohistochemical reaction for active caspase 3 was apparent after 30 minutes onwards predominantly in cortex. The controls were caspase 3 negative. The TUNEL staining was remarkable after 60 and 120 minutes. We detected a rapid onset of mucleolar segregation in cortical and subcortical neurons damaged by ischemia (15 min) reperfusion injury which coincides with a nuclear/nucleolar accumulation of MADD, a stress activated neuron specific death domain. Active caspase 3 and TUNEL positivity were found after a prolonged ischemia (30, 60 and 120 min.) |
| Related projects: |