It is known that excitotoxicity and oxygen radicals were two major pathogenic events related to mesial temporal sclerosis (MTS) , which was the most common histopathologic features in intractable temporal lobe epilepsy. The experiment was designed to investigate the neuroprotective effect of 2-methylaminochroman U-78517F, a second generation series of nonsteroidal lazaroid compounds, against excitotoxic and oxygen radical injuries on the human fetal hippocampal neurons in vitro. Neuron-enriched cultures were seeded on both 96 well multichamber plates and poly-L-lysine coated Aclar cover slips to determine cytotoxicity by MTT (3-4, 5-dimethylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide) assay and cytopathologic features respectively.
Dose-dependent neuronal injuries were developed by treatment of 100, 200, and 500μM glutamate(p<0.01), and 100μM hypoxanthine plus 10 to 20 mU xanthine oxidase (p<0.01) . The glutamate-induced cytotoxicity was completely blocked by pretreatment of 20μM MK-801(p<0.01), however, U-78517F did not attenuate the glutamate toxicity. The fetal hippocampal neurons were protected from oxygen radical injuries by pretreatment of 2 to 16μM U-78517F (p<0. 01) .
The cytopathologic changes observed by phase-contrast inverted microscope, neurofilament protein (NF) immunocytochemistry, and MTT stain correlated well with the degree of neuronal injuries in experimental groups. Considerably swollen neurons with disintegrated neurites were noted by the excitotoxic and oxygen radical injuries, however, there was no characteristic cytologic difference between them.
These data indicated that U-78517F had only a significant protective effect from oxygen radical injury on fetal hippocampal neurons in culture, and it was suggested that the early treatment of both glutamate-antagonists and antioxidants would be beneficial to reduce MTS following epileptic seizures.
|