烟酰胺对压力诱发兔腰椎间盘退变的保护作用(英文)

Protective effects of Niacinamide against axial loading induced degeneration of rabbit lumbar disc

背景:最近研究已经证实,烟酰胺能够促进椎间盘细胞的增殖并对椎间盘退变有改善作用。目的:验证烟酰胺对压力诱发的兔腰椎间盘退变的保护作用。设计、时间及地点:随机对照动物实验,于2008-11/2009-04在华中科技大学同济医学院附属协和医院中心实验室及骨科实验室完成。材料:4月龄日本大白兔24只,体质量2.0kg;烟酰胺为天津市大茂化学试剂厂产品。方法:取24只日本大白兔随机分入1～6组,采用可控轴向压力,以98N压力诱发椎间盘退变建立兔腰椎间盘退变模型,并按分组要求给予兔口服烟酰胺:第1组2只,安装加压装置不予加压或给药;第2组2只,给予50mg/kg烟酰胺口服1周;第3组5只,以98N压力加压1周;第4组5只,以98N压力加压1周,去除压力自行恢复1周;第5组5只,加压1周同时给予50mg/kg烟酰胺口服1周;第6组5只,自加压开始时持续给予50mg/kg烟酰胺,加压1周,然后去除压力后恢复1周。主要观察指标:以Thompson分级法及腰椎间盘磁共振评价退变程度;苏木精-伊红染色、Ⅱ型胶原免疫组织化学染色及藏红O-快绿染色考察其组织学改变;P16INK4A免疫组织化学染色检测细胞增殖和衰老状态的变化。结果:①第2组椎间盘未见明显退变;第3组5只动物Thompson分级均为Ⅱ级,第4组4只为Ⅱ级,1只为Ⅲ级,第5组2只为Ⅰ级,3只为Ⅱ级,第6组3只为Ⅰ级,2只为Ⅱ级。MRI也显示,服用烟酰胺的动物椎间盘退变程度有所减轻。②第6组纤维环Ⅱ型胶原含量较第4组高约53.2%(P<0.01)。③第2组藏红O染色强度较第1组有所上升;第5,6组髓核和纤维环染色强度均高于第4组的相对应部位,其中以第6组髓核上升最为明显(P<0.01,P<0.01),第6组较第5组有轻微上升。④P16INK4A阳性率随烟酰胺给药时间延长而降低。结论:烟酰胺有助于减轻压力对椎间盘的损伤,能够促进压力损伤后的椎间盘恢复。

BACKGROUND： Recent studies have demonstrated that Niacinamide is capable of promoting the proliferation of intervertebral cells and improving intervertebral disc degeneration. Overloading is thought to the main cause of intervertebral disc degeneration. However, the protective effects of Niacinamide in loading induced intervertebral disc degeneration remains uncertain. OBJECTIVE： To investigate the protective effects of Niacinamide against axial loading induced degeneration of rabbit lumbar disc. DESIGN, TIME AND SETTING： A randomized controlled experiment was carried out in the Central Laboratory and the Laboratory of Department of Orthopaedics, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology from November 2008 to April 2009. MATERIALS： Twenty-four Japanese white rabbits （4 months old, weighing 2.0 kg）. Niacinamide was supplied by Tianjin Damao Chemical Reagent Factory. METHODS： Twenty-four Japanese white rabbits were randomly divided into 6 groups. The controllable axial loading induced rabbit lumbar disc degeneration model was adopted to impose 98N pressure on the rabbit discs to induce degeneration. Various doses of Niacinamide were given intragastrically to the rabbits in different groups： 2 rabbits in group 1, the loading device was installed without pressing, and no Niacinamide was given; 2 rabbits in group 2, given 50 mg/kg Niacinamide for 1 week; 5 rabbits in group 3, loaded with 98N for 1 week; 5 rabbits in group 4, loaded with 98N for 1 week, then the pressure was released for another week＇s recovery; 5 rabbits in group 5, loaded with 98N and given 50 mg/kg Niacinamide for 1 week; 5 rabbits in group 6, loaded with 98N for 1 week and then the pressure was released for another week＇s recovery, 50 mg/kg Niacinamide was continually given during the 2 weeks. MAIN OUTCOME MEASURES： Magnetic resonance image and Thompson＇s grading system were used to assess degeneration degree of the discs; hematoxylin and eosin staining, immunohistochemical staining for type Ⅱ collagen, and Safranin O staining were used to evaluate histological changes; immunohistochemical staining for P16INK4A was used to evaluate cell proliferation and senescence. RESULTS： ①According to the Thompson＇s grading system, there was no disc exhibited degeneration in group 2; 5 rabbits graded Ⅱ in group 3; 4 rabbits graded Ⅱ and 1 rabbit graded Ⅱ in group 4; 2 rabbits graded Ⅱ and 3 rabbits graded Ⅱ in group 5; 3 rabbits graded Ⅱ and 2 rabbits graded Ⅱ in group 6. MRI results revealed the alleviated degeneration in Niacinamide given groups. ②The content of type Ⅱ collagen of annulus fibrosus of group 6 was 53.2% higher than that of group 4 （P 〈 0.01）. ③ Safranin O- Fast Green staining density of group 2 was higher than that of group 1; The staining density of nucleus pulposus and annulus fibrosus of groups 5 and 6 was higher than the corresponding parts of group 4, especially that of nucleus pulposus （P 〈 0.01, P 〈 0.01）, and group 6 exhibited slightly increased levels than group 5. ④P16INK4A positive staining rates decreased with the extension of Niacinamide administration time. CONCLUSION： Niacinamide can help to alleviate overloading-caused damage to intervertebral disc, and can benefit the recovery of damaged intervertebral disc.