Effect Of Anti-NF-κB Inhibitor PDTC In Preventing The Kidney Injury Of Pig After Brain Death

Brain-dead (BD) donor organs have been applied in transplantations. But the complications and mortality rate after transplantation using brain-dead donor were significantly higher than those using living donor.This showed that kidney from brain-dead donor was injuried before transplantion. Researches indicated that brain death can induce a variety of cytokines releasing and activate cytokine cascade through neuroendocrine system,leading to organ morphology and function injury. Nuclear factor kB(NF-kB) can regulate expressions of several genes, compacted to inflammatory reaction and immunologic response.Therefore,the realitionship between NF-κB and kidney injury after brain death is need to be reasearched. Pyrrolidine dithiocarbamate (PDTC) was considered NF-κB-specific inhibitors. It was showed PDTC can ameliorate kidney function and reduce kidney pathological damage in the model of endotoxin-induced multiple organ failure, FK506-induced nephropathy, nephrectomy-induced renal injury, vascular contraction-II-induced organ damage. However, whether PDTC can affect renal NF-κB activity in brain-dead state and play a protective role against the inflammatory injury or not, has not been reported. Therefore, further researches of NF-κB in the kidney damage after brain death and PDTC ameliorate kidney injury, will provide a theoretical basis for the protection of brain-dead donor.ObjectiveTo investigate the role of NF-κB on kidney injury after brain death in pig and the protective effects of PDTC on kidney injury.Materials and MethodsEightteen healthy pigs (25±4kg) were randomized into 3 groups: control group (n=6) was maintained anesthesia for 24h but not created brain-dead model; brain-dead group (n=6) was established brain-dead model by increasing intracranial pressure in a modified, slow and intermittent way, and maintained brain-dead state for 24h by respiration and circulation support; pyrrolidinedithiocarbamate (PDTC) treatment group (n=6) was induced brain-death as group Brain-death and injected PDTC (15mg/kg,100mL normal saline) at the first initial BD. Whereas control group and brain-dead group were injected 100mL normal saline in the corresponding points. The criteria for brain death were as following: a) deep coma; b) papillary reflex and corneal reflex disappear; c) spontaneous respirations cease; d) EEG is static; e) atropine test is negative; f) recheck time is after 12 hours interval. The conditions that meet the first 5 criterias are reaffirmed. Hemodynamics and vital sign are kept stable all the time. At 6, 12 and 24h after the initial brain death, 5ml blood was gained through inferior caval vein to determine serum TNF-α, BUN and Cr. At the same time renal tissues were taken, the changes of renal tissues were observed by HE staining.The level of tumor necrosis factor-α(TNF-α) by ELISA.Serum BUN and Cr were determined by auto-biochemical ananlysis instrument. The expressions of molynocyte chemoattractant protein-1 (MCP-1) were determined by immnohisto-chemistry. NF-κB mRNA and MCP-1 mRNA were detected by real time fluorescence quantitative PCR (RT-FQ-PCR).Results(1) Under light microscope, within 12h after the initial brain-death, there were slight renal proximal convoluted tubule cell edema, and at 24h, cytoplasm edema, mitochondrion swelling, no obvious morphological injury was observed under light microscope.(2) Serum BUN and Cr level: BUN and Cr for Control group had no significant difference at each time point; since 6h after the innial brain death, BUN and Cr for group Brain-death and group PDTC began to increase. BUN and Cr at 6, 12 and 24h had significant differences (P<0.05); and compared with group PDTC, BUN and Cr for group Brain-death were significantly higher at each time point (PO.05).(3) Serum TNF-αlevel:TNF-αfor Control group had no significant difference at each time point; since 6h after the innial brain death, TNF-αfor group Brain-death and group PDTC began to increase. TNF-αat 6,12 and 24h had significant differences (P<0.05);and compared with group PDTC,TNF-αfor group Brain-death were significantly higher at each time point (PO.05).(5) Changes of NF-κB mRNA in kidney cells NF-κB mRNA expression for group Control at each time point had no significant difference, while these parameters for group Brain-death and PDTC began to increase since 6h. The expression of NF-κB mRNA at 6,12and 24h had significant differences(P<0.05), which was significantly higher for group Brain-death than that for group PDTC at each time point(P0.05).(4) Expression of MCP-1 protein and MCP-1 mRNA: Expression of MCP-1 protein and mRNA for group Control at each time point had no significant difference while that for group Brain-death and PDTC began to increase since 6h. MCP-1 protein and mRNA expression at 6,12 and 24h had significant differences(P<0.05); which were significantly higher for group Brain-death than those for group PDTC at each time point (P<0.05).ConclusionsBrain death can cause kidney injury, NF-κB plays an important role.And PDTC ,the inhibitor of NF-κB, can protect the kidney from the injury.