Hydrogen-Rich Saline Is Cerebroprotective In A Rat Model Of Deep Hypothermic Circulatory Arrest And Its Mechanism Study

Deep hypothermia circulation arrest (DHCA) has been used in the surgical repair of complex congenital heart malformations and the operations involving the aortic arch and brain aneurysm as it can provide a quiet, dry and motionless surgical field for a perfect operation. However, the long duration of DHCA results in some severe neurological complications which contribute substantially to postoperative mortality and morbidity. How to limit the neurological complications of DHCA is a critical issue that must be solved practically. The pathophysiology of DHCA mainly consists of the systemic inflammatory response syndrome (SIRS) caused by cardiopulmonary bypass and the ischemia-reperfusion (I/R) injury associated with circulatory arrest. Recently, Ohsawa demonstrated that hydrogen (H2) ameliorates focal ischemic injury in adult rats, the mechanisms may be related to direct consumption of free radical such as ·OH by H2. It is also reported that H2 saturated water could attenuate superoxide formation in ex vivo mouse brain slices with diminished endogenous free radical buffering capacity. Similar result has been observed in chronically restrained mice and the rat model of carbon monoxide encephalopathy, mild hypoxia-ischemia model of neonatal rats, intestinal I/R model, myocardial ischemia model, contused spinal cord injury model, chronic liver inflammation and arteriosclerosis patients.Accumulated data suggested that the H2 could therapy I/R lesions by mechanisms involving anti-inflammation and anti-oxidation. However, the effects of H2 on brain injury induced by DHCA have not yet been reported. Prompted by the previous findings, we hypothesized that the H2 was able to effectively ameliorate the brain injury induced by DHCA by mechanisms involving anti-inflammation and/or anti-oxidation.PART ONE:Hydrigen-Rich Saline Has Cerebropro-tective Effect on Rat Model of DHCAOBJECTIVE:to identify whether the hydrogen has cerebroprotection on the rat model of DHCA.METHODS:Firstly we set up a cerebroprotective rat model of DHCA. We devided the rats in three groups that included sham-operation group, DHCA group and hydrogen treated DHCA (DHCA+H2) group. We evaluated the general condition and morbidity during the 24 hours postoperatively. We also assessed the brain water contents and the activity of caspase 3, checked the pathologic change by HE staining, TUNEL staining and transmission electron microscopy (TEM) in the CA1 area of hippocampus.RESULTS:DHCA could increase the rats’morbidity, exacerbate the general condition, elevate the brain water content and strengthen the caspase 3 activity in brain tissue compared with that of rats in sham-opertion group in the first 24 hours postoperatively. The HE staining and TEM change of CA1 area in hippocampus showed us that the neuron loss and the apoptosis index (AI) increased in 72 hours postoperatively. The hydrogen-rich saline treatment to DHCA rats could decrease the brain water content, improve the general condition, decrease the morbidity and down-regulate the caspase 3 activity in brain tissue, the HE staining, TUNEL staining and TEM changes of CA1 area in hippocampus showed a decreases intency of neuron loss and apoptosis index.CONCLUSION:DHCA could cause severe brain injury, hydrogen-rich saline could effetively protect brain tissue by decreasing the brain injury induced by DHCA.PART TWO:The Cerebroprotective Mechanism Study of Hydrogen-Rich Saline Tharapy on Rat Model of DHCAOBECTIVE:We have known that the hydrogen had the cerebroprotective effects in DHCA rat model, but what is the main protective mechanism is still unknown. Here we designed to explore the mechanism whether it is about anti-inflammation and/or anti-oxidation.METHODS:Firstly we set up a cerebroprotective rat model of DHCA. We devided the rats in three groups that included sham-operation group, DHCA group and hydrogen treated DHCA (DHCA+H2) group as part one. We assayed the inflammatory factors such as TNF-a, IL-1β and NF-κB in serum and brain tissue in 24 hours postoperatively. We also examinined the oxidative markers such as MDA, 8-OH-dG, NOS and SOD in serum and brain tissue in 24 hours postoperatively.RESULTS:There have an elevated level of inflammatory factors such as TNF-a, IL-1β and NF-κB and an increased level of oxidation markers such as MDA, 8-OH-dG and NOS while a decreased activity of SOD in serum and brain tissue compared with that in sham operation group. The hydrogen-rich saline treatment to the DHCA rats could decrease the inflammatory factors including TNF-a, IL-1β and NF-κB, the change of oxidative markers such as MDA,8-OH-dG and NOS was decreased while SOD activity was increased in serum and brain tissue compared with that in DHCA group.CONCLUSION:Hydrogen-rich saline has cerebroprotective effects by mechanism involving of anti-inflammation and anti-oxidation.