Ghrelin及NF-κB在急性坏死性胰腺炎并肝损伤中的作用

Role of ghrelin and NF-κB in the pathogenesis of acute necrotizing pancreatitisassociated liver injury

目的:观察Ghrelin、NF-κB在大鼠急性坏死性胰腺炎并肝损伤及褪黑素干预时在肝脏中的表达,探讨两者在其中的作用及褪黑素对Ghrelin的影响和可能机制.方法:72只♂SD大鼠随机分为对照组(C组,n=24)、急性坏死性胰腺炎组(A组,n=24)、褪黑素干预组(M组,n=24).A组分3次腹腔注射6%左旋精氨酸(L-Arg)1.5g/kg,诱发急性坏死性胰腺炎,C组同法注射等量生理盐水,M组在首次注射L-Arg前0.5h腹腔注射1%褪黑素50μg/kg.各组大鼠在末次腹腔注射后6、12、24h分批处死.光镜下观察胰腺及肝脏病理改变并进行评分,测定血清淀粉酶水平,RT-PCR检测肝脏Ghrelin及NF-κBmRNA水平,Westernblot检测肝NF-κB蛋白表达.结果:A组各时点胰腺及肝脏病理评分、血清淀粉酶、肝NF-κBmRNA(6h:0.74±0.04vs0.40±0.05;12h:0.77±0.03vs0.40±0.02;24h:0.82±0.04vs0.40±0.03,均P=0.000)及蛋白表达(24h:0.48±0.07vs0.16±0.04,P=0.000)均较C组显著升高(均P<0.01).GhrelinmRNA较C组明显降低(6h:0.39±0.04vs0.66±0.03;12h:0.14±0.37vs0.30±0.05;24h:0.22±0.02vs0.59±0.05,均P=0.000).M组各时点胰腺及肝脏病理评分、血清淀粉酶、肝NF-κBmRNA(6h:0.50±0.05vs0.74±0.04;12h:0.54±0.04vs0.77±0.03;24h:0.57±0.03vs0.82±0.04,均P<0.05)及蛋白表达(24h:0.32±0.04vs0.48±0.07,P<0.05),均较A组显著降低(均P<0.05).GhrelinmRNA较A组升高(6h:0.54±0.03vs0.39±0.04;12h:0.40±0.09vs0.30±0.05;24h:0.39±0.04vs0.22±0.02,均P<0.05).结论:Ghrelin在急性胰腺炎并肝损伤时的表达可能与病变严重程度有关;NF-κB在该病变发展过程中起了重要作用,外源性褪黑素可以减轻急性胰腺炎的胰腺和肝脏病变,该保护作用可能与提高Ghrelin的表达、下调NF-κB的活性有关.

AIM：To investigate the expression of ghrelin in the liver of rats with acute necrotizing pancreatitis（ANP） with liver injury and to explore the role of ghrelin and NF-κB in the pathogenesis of ANP-associated liver injury and the mechanism underlying the therapeutic effects of melatonin against ANP.METHODS：Seventy-two male Sprague-Dawley rats were randomly and equally divided into control group,ANP group,and melatonin intervention group.Rats of the ANP group and melatonin intervention group were injected with 6% L-Arg（1.5 g/kg） intraperitoneally three times to induce ANP.Rats of the control group were injected with same volume of normal saline.The melatonin intervention group was given 1% melatonin（50 μg/kg） intraperitoneally 0.5 h before the first injection of L-Arg.Rats were sacrificed at 6,12,and 24 h after the injection of melatonin.Pathological changes in the pancreatic and hepatic tissue were observed and graded under a microscope.The expression of ghrelin and NFκB mRNAs was evaluated by RT-PCR,while the protein expression of NF-κB was detected by Western blot.RESULTS：Pancreatic and hepatic pathological scores,serum amylase,and expression of NFκB mRNA（6 h：0.74 ± 0.04 vs 0.40 ± 0.05;12 h：0.77 ± 0.03 vs 0.40 ± 0.02;24 h：0.82 ± 0.04 vs 0.40 ± 0.03,all P = 0.001） and protein in the liver at all time points were signif icantly higher（24 h：0.48 ± 0.07 vs 0.6 ± 0.04,P 0.05）,and ghrelin mRNA expression was significantly lower in the ANP group than in the control group（6 h：0.39 ± 0.04 vs 0.66 ± 0.03;12 h：0.14 ± 0.37 vs 0.30 ± 0.05;24 h：0.22 ± 0.02 vs 0.59 ± 0.05,all P 0.05）.Pancreatic pathological scores,hepatic pathological scores,serum amylase,and expression of NF-κB mRNA（6 h：0.50 ± 0.05 vs 0.74 ± 0.04,12 h：0.54 ± 0.04 vs 0.77 ± 0.03,24 h：0.57 ± 0.03 vs 0.82 ± 0.04,all P 0.05） and protein were decreased（24 h：0.32 ± 0.04 vs 0.48 ± 0.07,P 0.05）,and ghrelin mRNA expression was elevated（6 h：0.54 ± 0.03 vs 0.39 ± 0.04,12 h：0.40 ± 0.09 vs 0.30 ± 0.05,24 h：0.39 ± 0.04 vs 0.22 ± 0.02,all P 0.05） in the melatonin intervention group compared with in the ANP group.CONCLUSION：The expression of ghrelin may be related to the severity of ANP with liver injury.NF-κB may also be involved in the pathogenesis of ANP with liver injury.Exogenous melatonin can reduce ANP possibly by up-regulating ghrelin expression and down-regulating NF-κB expression.