孕酮通过NF-κB调控脑损伤后大鼠海马神经元COX-2和Caspase-3的表达

Progesterone regulates COX-2 and Caspase-3 expressions in hippocampal neurons in rats after traumatic brain injury by NF-κB signaling pathway

目的研究NF-κB对脑损伤大鼠海马神经元环氧合酶-2(COX-2)、半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)的表达调控作用,探讨孕酮(progesterone,PROG)对脑损伤(TBI)后大鼠海马神经元保护作用及其可能机制。方法雄性SD大鼠45只按抛硬币法分为假手术组、损伤组和PROG组,按照改良的Feeney自由落体损伤装置制作大鼠脑损伤模型,用Nissl染色法、免疫组织化学法及免疫蛋白印记法,观察大鼠伤侧海马CA1区NF-κB、COX-2以及Caspase-3的表达变化和孕酮对上述指标变化的影响。结果损伤组大鼠海马CA1区NF-κB(24.0±2.5)、COX-2(35.9±2.7)、Caspase-3(25.1±2.7)阳性神经元的数量较假手术组NF-κB(1.9±0.9)、COX-2(1.5±0.7)、Caspase-3(1.8±0.8)显著增加(P<0.05);PROG组与损伤组比较,海马CA1区NF-κB(14.2±1.8)、COX-2(16.6±2.7)、Caspase-3(11.2±2.4)阳性神经元的数量明显减少(P<0.05)。结论NF-κB对脑损伤后大鼠海马神经元COX-2和Caspase-3表达起调控作用;PROG通过NF-κB对脑损伤后大鼠海马神经元起保护作用。

Objective To investigate the effect of nuclear factor-κB（NF-κB） on the regulation of cyclooxygenase-2（COX-2） and Caspase-3 in hippocampal neurons after traumatic brain injury（TBI） in rats,and explore the neuroprotective effect and the possible mechanism of progesterone（PROG） in hippocampal neurons after TBI.Methods Forty-five male Spraque-Dawley rats were randomly divided into 3 groups： sham-operated group（n=15）,TBI group（n=15） and PROG-treated group（n=15,intraperitoneal injection of PROG 16 mg/kg in 1 and 6 h after injury）.The rat model of TBI was duplicated with the improved Feeney＇s method.The rats were sacrificed in 24 h after injury and their brain was resected.Nissl staining,immunohistochemical staining and Western blot assay for NF-κB,COX-2 and Caspase-3 was used to observe the changes of positive cell numbers and protein levels in the hippocampal neurons.Results The numbers of immunoreactive neurons to NF-κB（24.0±2.5）,COX-2（35.9±2.7） and Caspase-3（25.1±2.7） were significantly increased in the hippocampus at 24 h after TBI when compared with the positive neuron numbers of NF-κB（1.9±0.9）,COX-2（1.5±0.7） and Caspase-3（1.8±0.8） in sham group.After the treatment of PROG,the positive cell number of NF-κB（14.2±1.8）,COX-2（16.6±2.7）,Caspase-3（11.2±2.4） was reduced obviously as compared with the TBI group（P0.05）.Conclusion NF-κB signaling pathway may play an important role in the regulation of COX-2 and Caspase-3 in the hippocampus neurons after TBI in rats.PROG may influence the expression of NF-κB and protect the hippocampal neurons.