Monitoring Changes in the Redox State of Myoglobin in Cardiomyocytes by Raman Spectroscopy Enables the Protective Effect of NO Donors to Be Evaluated
journal contributionposted on 26.10.2015, 10:37 by Andrew Hudson, Abdullah Almohammedi, Sofia M. Kapetanaki, Nina M. Storey
Raman microspectroscopy has been used to monitor changes in the redox and ligand-coordination states of the heme complex in myoglobin during the pre-conditioning of ex vivo cardiomyocytes with pharmacological drugs that release nitric oxide (NO). These chemical agents are known to confer protection on heart tissue against ischemia-reperfusion injury. Subsequent changes in the redox and ligand-coordination states during experimental simulations of ischemia and reperfusion have also been monitored. We found that these measurements, in real time, could be used to evaluate the pre-conditioning treatment of cardiomyocytes, and predict the likelihood of cell survival following a potentially-lethal period of ischemia. Evaluation of the pre-conditioning treatment was done at the single-cell level. The binding of NO to myoglobin, giving a 6-coordinate ferrous-heme complex, was inferred from the measured Raman bands of a cardiomyocyte by comparison to pure solution of the protein in the presence of NO. A key change in the Raman spectrum was observed after perfusion of the NO-donor was completed, where if the pre-conditioning treatment was successful then the bands corresponding to the nitrosyl complex were replaced by bands corresponding to metmyoglobin, Mb[SUPERSCRIPT: III]. An observation of Mb[SUPERSCRIPT: III] bands in the Raman spectrum was made for all the cardiomyocytes that recovered contractile function, whilst the absence of Mb[SUPERSCRIPT: III] bands always indicated that the cardiomyocyte would be unable to recover contractile function, following the simulated conditions of ischemia and reperfusion in these experiments.