For our study published in this month’s issue of the journal
, we tried to determine whether there was any advantage in using one anesthetic over another with regard to their neurotoxic properties. More specifically, we sought to determine the effects of inhalation agents on the developing brain.
In order to compare equipotent doses, we first had to determine minimum alveolar concentrations (MAC) for desflurane, isoflurane, and sevoflurane in 7-day-old mice, the values of which were not previously known. Figure 1 from the manuscript shows the results of the MAC determination (please refer to the manuscript for further details).
Subsequently, using clinically significant equipotent concentrations of the three inhaled anesthetics, two independent methods were used to quantify caspase-3 expression, the central effector enzyme of the apoptotic cell death cascade. Senior research assistant John McCann prepared microtiter plates to measure caspase-3 expression with a colorimetric assay. The figure (fig 5 from the manuscript) shows quantification of the assay.
Research assistant Elizabeth Hughes cut and stained brain sections for the apoptotic marker, activated –caspase-3 (seen as light green dots in a portion of figure 3 from the manuscript), and the neuronal marker NeuN.
She further obtained image stacks using confocal microscopy and transferred them into brain mapping software. Dr. George Istaphanous then quantified and analyzed neuronal apoptosis in the mouse neocortex, as seen in this figure from the manuscript.
Our findings demonstrate similar degrees of neuroapoptosis when using equipotent doses of desflurane, isoflurane, and sevoflurane, suggesting that developmental neurotoxicity is a common feature of all three drugs. Additional research is planned.
This visit to the lab was hosted by Dr. Andreas Loepke.
Research is a team undertaking. He would like to thank all contributors for their effort and support in completing this important study.