Zamora T, Palma J, Andia M, Garcia P, Wozniak A, Solar A, Campos M
Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, 362, Diagonal Paraguay, 8330077 Santiago, Chile.
Department of Radiology, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
Orthop Traumatol Surg Res. 2017 Sep;103(5):795-799. doi: 10.1016/j.otsr.2017.04.005. Epub 2017 May 25.
Multiple reports of bacterial isolates in human disc tissue have suggested a role of low-grade infection on intervertebral disc degeneration and modic changes (MC) generation. Animal models have been extensively used to study IDD; however, until recently, no consideration had been given to eventual infectious processes. To reproduce the phenomena by inoculating an infecting agent would support the infectious hypothesis. Therefore, we studied the effect of Propionibacterium acnes (PA) inoculation on rat-tails and determined whether it would produce MCs on the adjacent endplates.
Disc infection with PA would accelerate IDD compared with the standard model and would also lead to MCs on the adjacent endplates.
Twelve Sprague-Dawley rats were randomized to receive a needle puncture in a caudal tail disc with either saline (control) or an inoculum of 5×10 CFU of strain 1a PA. Twelve weeks later, the rats were euthanized and the tails were analyzed. The main assessment criteria were obtained from the post-mortem MRI: T2 values of punctured discs and adjacent endplates, as well as disc volumes. A histological grading score for IDD was also used, measuring the morphology and cellularity of the nucleus and annulus, as well as endplate disruption.
The median T2 value and disc volume were smaller in PA-punctured discs [T2 value: 30ms (23-44) vs. 61ms (38-132), respectively, P=0.01; 0.01mm (0.01-0.05) vs. 0.5mm (0.01-5.35), respectively; P=0.049]. There was no change in the adjacent endplates. There was no significant difference in histological grading between the test and control [13 (10-14) vs. 10.5 (6-13); P=0.05].
Inoculation of caudal discs with PA generated increased degeneration; however, no MCs were observed on the adjacent endplates. A better understanding of low-grade disc infections is still needed.
V (animal study).
多项关于人体椎间盘组织中细菌分离株的报告表明，低度感染在椎间盘退变和Modic改变（MC）的发生中起作用。动物模型已被广泛用于研究椎间盘退变（IDD）；然而，直到最近，尚未考虑到可能存在的感染过程。通过接种感染因子来重现这些现象将支持感染假说。因此，我们研究了痤疮丙酸杆菌（PA）接种对大鼠尾巴的影响，并确定其是否会在相邻终板上产生Modic改变。
与标准模型相比，PA感染椎间盘会加速IDD，并导致相邻终板出现Modic改变。
将12只Sprague-Dawley大鼠随机分为两组，一组在尾椎椎间盘进行针刺并注射生理盐水（对照组），另一组注射5×10 CFU的1a型PA菌株接种物。12周后，对大鼠实施安乐死并分析尾巴。主要评估标准来自死后MRI：穿刺椎间盘和相邻终板的T2值以及椎间盘体积。还使用了IDD的组织学分级评分，测量髓核和纤维环的形态和细胞密度以及终板破坏情况。
PA穿刺椎间盘的T2值中位数和椎间盘体积较小 [T2值分别为：30ms（23 - 44）对61ms（38 - 132），P = 0.01；0.01mm（0.01 - 0.05）对0.5mm（0.01 - 5.35），P = 0.049]。相邻终板无变化。试验组和对照组在组织学分级上无显著差异 [13（10 - 14）对10.5（6 - 13）；P = 0.05]。
PA接种尾椎椎间盘会导致退变增加；然而，在相邻终板上未观察到Modic改变。仍需要更好地理解低度椎间盘感染。
V（动物研究）
