Zhang Chao, Kong Xiaohong, Ning Guangzhi, Liang Zhipin, Qu Tongjun, Chen Feiran, Cao Daigui, Wang Tianyi, Sharma Hari S, Feng Shiqing
Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, China.
School of Medicine, Nankai University, Tianjin 300071, China.
Neuropharmacology. 2014 Apr;79:275-81. doi: 10.1016/j.neuropharm.2013.11.010. Epub 2013 Dec 4.
Laminectomy is a widely accepted treatment for lumbar disorders, and epidural fibrosis (EF) is a common complication. EF is thought to cause post-operative pain recurrence after laminectomy or discectomy. All-trans retinoic acid (ATRA) has shown anti-fibrotic, anti-inflammatory, and anti-proliferative functions. The object of this study was to investigate the effects of ATRA on the prevention of EF in post-laminectomy rats. In vitro, the anti-fibrotic effect of ATRA was demonstrated with cultured fibroblasts count, which comprised of those that were cultured with/without ATRA. In vivo, rats underwent laminectomy at the L1-L2 levels. We first demonstrated the beneficial effects using 0.05% ATRA compared to vehicle (control group). We found that a higher concentration of ATRA (0.1%) achieved dose-dependent results. Hydroxyproline content, Rydell score, vimentin-positive cell density, fibroblast density, inflammatory cell density and inflammatory factor expression levels all suggested better outcomes in the 0.1% ATRA rats compared to the other three groups. Presumably, these effects involved ATRA's ability to suppress transforming growth factor (TGF-β1) and interleukin (IL)-6 which was confirmed with reverse-transcriptase polymerase chain reaction (RT-PCR). Finally we demonstrated that ATRA down-regulated nuclear factor (NF)-κB by immunohistochemistry and western blotting for p65 and inhibition of κB (IκBα), respectively. Our findings indicate that topical application of ATRA can inhibit fibroblast proliferation, decrease TGF-β1 and IL-6 expression level, and prevent epidural scar adhesion in rats. The highest concentration employed in this study (0.1%) was the most effective. ATRA suppressed EF through down-regulating NF-κB signaling, whose specific mechanism is suppression of IκB phosphorylation and proteolytic degradation.
椎板切除术是治疗腰椎疾病广泛采用的方法，而硬膜外纤维化（EF）是一种常见并发症。EF被认为会导致椎板切除术后或椎间盘切除术后疼痛复发。全反式维甲酸（ATRA）已显示出抗纤维化、抗炎和抗增殖功能。本研究的目的是探讨ATRA对预防椎板切除术后大鼠EF的作用。在体外，通过对培养的成纤维细胞计数（包括在有/无ATRA条件下培养的细胞）证明了ATRA的抗纤维化作用。在体内，大鼠在L1-L2水平接受椎板切除术。与载体（对照组）相比，我们首先证明了使用0.05% ATRA的有益效果。我们发现较高浓度的ATRA（0.1%）产生了剂量依赖性结果。羟脯氨酸含量、Rydell评分、波形蛋白阳性细胞密度、成纤维细胞密度、炎性细胞密度和炎性因子表达水平均表明，与其他三组相比，0.1% ATRA组大鼠的结果更好。据推测，这些作用涉及ATRA抑制转化生长因子（TGF-β1）和白细胞介素（IL）-6的能力，这通过逆转录聚合酶链反应（RT-PCR）得到证实。最后，我们分别通过免疫组织化学和针对p65的蛋白质印迹法以及κB抑制蛋白（IκBα）证明了ATRA下调核因子（NF）-κB。我们的研究结果表明，局部应用ATRA可抑制成纤维细胞增殖，降低TGF-β1和IL-6表达水平，并预防大鼠硬膜外瘢痕粘连。本研究中使用的最高浓度（0.1%）最为有效。ATRA通过下调NF-κB信号传导抑制EF，其具体机制是抑制IκB磷酸化和蛋白水解降解。
