The Roles Of Ulinastatin On Mitochondrial Pathways In Apoptosis And Autophagy Of Rat Brain Cells After Cardiopulmonary Resuscitation

Objectives:How to care post-cardiac arrest brain injury has become a focus of cardiopulmonaryresuscitation recently. The existing evidences suggest that UTI can produce protectiveeffects and mitigate the damage of the nerve cells of the cerebral cortex through a varietyof signal pathways, during cerebral ischemia-reperfusion injury. Theoretically,ulinastatin (UTI) can stabilize the lysosomal membrane and inhibit the release oflysosomal enzymes, which can contribute to eliminating the damaged cytoplasmicproteins and organelles，moreover can affect the apoptosis by mitochondrial pathways.Therefore, the purpose of this proposal is to observe the roles of UTI on apoptosis andautophagy, mitochondrial injury, expression of markers-associated apoptosis andautophagy (e.g. Bax, Bcl-2, Caspase-3, beclin-1and LC3) in rat brain cells aftercardiopulmonary resuscitation to prove whether UTI can inhibit apoptosis, promoteautophagy and eventually, alleviate the brain injury after cardiac arrest.Methods:Our research was processed in three parts. In the first two parts, CA/CPR(cardiacarrest/cardiopulmonary resuscitation) model was established by percutaneous electricalstimulation of epicardial, and CPR was prosessed in Utstein mode6mins later in72rats,which were randomized into two groups: UTI group (treated with UTI, UTI group) andcontrol group(treated with NS, NS group). After ROSC (return of spontaneouscirculation), UTI (5000U/Kg, dissolved in1ml NS) was injected intraperitoneally q8h tillthe endpoint in UTI group, and control group as the same but with equal NS instead. Inthe third part, another8rats without modeling were randomized into two groups,sacrificed24hrs after injection of UTI or NS once as primary endpoint (day0). Relatedparameters were observed at1,3and7-day post CPR on experimental group.Results:1) At the1,3and7-day post CPR, AIs of TUNEL-positive cells, apoptosis underelectron microscopy and IODs of pro-apoptotic factors(bax and Caspase-3) expressionwere less in the cerebral cortex and the CA1region of hippocampin UTI groups thancontrol groups (P<0.05). In contrast, anti-apoptotic factorbcl-2, IODs of autophagymarkers (beclin-1and LC3B) expression and autophagy under electron microscopy weremore than control groups (P<0.05).2) At the1,3and7-day post CPR, less average ROSof mitochondria in cerebral cells, higher RFU of MMP and MPTP and lower Flamengscores of mitochondrial injury in cortical and hippocampal CA1neurons were observedin UTI groups than control groups.3) The expressions of bax, bcl-2, LC3A and LC3Bwere significantly increased after CA/CPR, which were very low at day0. Compared to the control groups, ratio and LR of mRNA of bax and bcl-2was much more lower(P<0.05) and ratio and LR of mRNA of LC3B and LC3A was increase significantly(P<0.05) in UTI groups.Conclusion:In CA6mins model of rats, UTI can1) inhibit the apoptosis of cerebral cells viamitigating the damage of mitochondria;2) inhibit the expression of pro-apoptotic factors(e.g. bax, Caspase-3);3) promote the expression of anti-apoptotic factor bcl-2andinfluence the balance of bax/bcl-2;4) promote autophagy to accelerate the repairment ofdamaged tissues.