beta-Amyloid-mediated inhibition of redox activity (MTT reduction) is not an indicator of astroglial degeneration.
The reduction in 3-[4,5-dimethylthiazol]-2,5-diphenyltetrazolium bromide (MTT) to a coloured formazan compound by cultured cells has been extensively used as an in vitro model for understanding neurobiological mechanisms involved in amyloid beta-protein (A beta-mediated cell death. In primary cultures of astrocytes, very low concentrations of aggregated A beta 1-4C, but not A beta 4C-1, produced a significant inhibition in the reduction of the dye MTT. This inhibitory response was rapid and persisted as long as A beta 1-4C was present in the culture medium. Such a severe reduction in cell redox activity for days failed to cause death of astroglial cells, measured in terms of trypan blue uptake and lactate dehydrogenase release. Interleukin-1 beta (IL-1 beta), which is known to attenuate excitotoxic neurodegeneration, had no effect on A beta 1-4C-induced inhibition of MTT reduction. These results suggest that even though inhibition of MTT reduction represents an early indicator of the A beta 1-4C mediated cell injury, without other corroborating evidence, it should not be used as a measure of cell death.
Department of Biochemistry, Charing Cross and Westminster Medical School, London, UK.
A J
AJ
Patel
S
S
Gunasekera
A
A
Jen
H A
HA
Rohan de Silva
D016564:Amyloid beta-Protein Precursor / Q000494:pharmacology*; D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D002478:Cells, Cultured / Q000187:drug effects; D007770:L-Lactate Dehydrogenase / Q000187:drug effects*; D009410:Nerve Degeneration / Q000187:drug effects*; D010084:Oxidation-Reduction / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D016564:Amyloid beta-Protein Precursor; D007770:L-Lactate Dehydrogenase