2014 年 63 巻 2 号 p. 227-234
To establish a minimally invasive rat model of lumbar intervertebral disc degeneration (IDD) to better understand the pathophysiology of the human condition. The annulus fibrosus of lumbar level 4–5 (L4-5) and L5-6 discs were punctured by 27-gauge needles using the posterior approach under C-arm fluoroscopic guidance. Magnetic resonance imaging (MRI), histological examination by hematoxylin and eosin (H&E) staining, and reverse transcription polymerase chain reaction (RT-PCR) were performed at baseline and 2, 4, and 8 weeks after disc puncture surgery to determine the degree of degeneration. All sixty discs (thirty rats) were punctured successfully. Only two of thirty rats subjected to the procedure exhibited immediate neurological symptoms. The MRI results indicated a gradual increase in Pfirrmann grade from 4 to 8 weeks post-surgery (P<0.05), and H&E staining demonstrated a parallel increase in histological grade (P<0.05). Expression levels of aggrecan, type II collagen (Col2), and Sox9 mRNAs, which encode disc components, decreased gradually post-surgery. In contrast, mRNA expression of type I collagen (Col1), an indicator of fibrosis, increased (P<0.05). The procedure of annular puncture using a 27-gauge needle under C-arm fluoroscopic guidance had a high success rate. Histological, MRI, and RT-PCR results revealed that the rat model of disc degeneration is a progressive pathological process that is similar to human IDD.