Low-dose nitroglycerine improves outcome after cardiac arrest in rats

Objective

The aim of this study was to evaluate the outcome of intravenously applied nitroglycerine (NTG, 1 μg kg⁻¹ min⁻¹ for 1 h) after resuscitation from an asphyxia cardiac arrest (ACA) insult. We hypothesized that NTG infused for 1 h after the return of spontaneous circulation (ROSC) would improve functional and neuro-morphological outcomes.

Methods

Adult rats were subjected to 8 min of ACA followed by resuscitation. There were three treatment groups: ACA, ACA + NTG and sham operated. Vital and blood parameters were monitored during the 1 h post-resuscitation intensive care phase. After survival times of 3, 6, 12, 24, 72 h and 7 days, the neurological deficit score (NDS) was measured. Histological evaluation of the hippocampus, cortex, the thalamic reticular nucleus and the caudate-putamen was performed 7 days post insult.

Results

We found that NTG (i) induced significantly higher initial MAP peaks; (ii) resulted in a less-pronounced elevation of heart rates after ROSC with significantly faster normalization to baseline levels; and (iii) influenced glucose metabolism, temporarily elevating blood glucose to non-physiological levels. Even so, NTG (iv) improved the neurological outcome and (v) reduced neurodegeneration, mainly in the hippocampal CA1 region. A significant NTG-associated decrease in blood pressure did not occur.

Conclusion

The effect of low-dosed NTG applied post-resuscitation appears to be neuroprotective, demonstrated by reduced hippocampal damage and a better NDS, even with temporarily elevated blood glucose to non-physiological levels. Thus, additional studies are needed to evaluate NTG-triggered mechanisms and optimized dosages before clinical translation should be considered.Animal study institutional protocol number: 42502-2-2-947-Uni-MD.