Lichao Sun, Shouqin Ji and Jihong Xing* Pages 4310 - 4317 ( 8 )
Background/Aims: Central pro-inflammatory cytokine (PIC) signal is involved in neurological deficits after transient global ischemia induced by cardiac arrest (CA). The present study was to examine the role of microRNA- 155 (miR-155) in regulating IL-1β, IL-6 and TNF-α in the hippocampus of rats with induction of CA. We further examined the levels of products of oxidative stress 8-isoprostaglandin F2α (8-iso PGF2α, indication of oxidative stress); and 8-hydroxy-2’-deoxyguanosine (8-OHdG, indication of protein oxidation) after cerebral inhibition of miR-155.
Methods: CA was induced by asphyxia and followed by cardiopulmonary resuscitation in rats. ELISA and western blot analysis were used to determine the levels of PICs and products of oxidative stress; and the protein expression of NADPH oxidase (NOXs) in the hippocampus. In addition, neurological severity score and brain edema were examined to assess neurological functions.
Results: We observed amplification of IL-1β, IL-6 and TNF-α along with 8-iso PGF2α and 8-OHdG in the hippocampus of CA rats. Cerebral administration of miR-155 inhibitor diminished upregulation of PICs in the hippocampus. This also attenuated products of oxidative stress and upregulation of NOX4. Notably, inhibition of miR-155 improved neurological severity score and brain edema and this was linked to signal pathways of PIC and oxidative stress.
Conclusion: We showed the significant role of blocking miR-155 signal in improving the neurological function in CA rats likely via inhibition of signal pathways of neuroinflammation and oxidative stress, suggesting that miR-155 may be a target in preventing and/or alleviating development of the impaired neurological functions during CA-evoked global cerebral ischemia.
microRNA-155, cardiac arrest, cardiopulmonary resuscitation, hippocampus, protein oxidation, asphyxia.
Department of Emergency Medicine, The First Hospital of Jilin University, Changchun, Jilin 130021, Jiutai District People's Hospital of Changchun, Changchun, Jilin 130500, Department of Emergency Medicine, The First Hospital of Jilin University, Changchun, Jilin 130021