Establishment of a rat caudal disc degeneration model by percutaneous fine-needle aspiration of the fibrous ring / 中国医师杂志

ABSTRACT

Objective To compare the effect of different size needle gauges to the degenerative response in rat caudal discs.Methods A total of 40 Sprague Dawley (SD) rats,level 5/6,7/8 and 9/10 interverbral discs of rat caudal spine were punctured with 18 or 21 or 25-gauge needles respectively.Radiographs and magnetic resonance imaging (MRI) were obtained at 1,2,4 and 6 weeks postsurgery.At each time point,ten rats from each group were sacrificed for histological analysis.Real-time fluorescent quantitative polymerase chain reaction (qPCR) was used to examine mRNA expression level.Results Significant differences were identified in the disc height index (DHI ％) and MRI grade between 18 G and normal group,MRI grade,histological score between 21 G and normal group at 2,4,and 6 weeks postsurgery.Significant differences were also identified in the histological score and mRNA expression levels between 18 G and normal group,alcian blue stain and hypoxia inducible factor-1α (HIF-1 α) mRNA expression level between 21G and normal group at all time point postsurgery.Significant differences existed in DHI％,type Ⅱ collagen and aggrecan mRNA expression levels between 21 G and normal group,all type mRNA expression levels between 25 G and normal group at 4,6 weeks.There were significant differences in MRI grade and histological score between 25 G and normal group at 6 weeks.Significant differences existed in almost all parameters compared between 18 G and 25 G at all time point.There were significant differences in DHI％,MRI grade,histological score and HIF-1α mRNA expression levels between 18 G and 21 G at 4,6 weeks.There were significant differences in type Ⅱ collagen and aggrecan mRNA expression levels between 18 G and 21 G at all time point.Significant differences exist in DHI％ and HIF-1α mRNA expression level between 21 G and 25 G at 6 weeks.Compared with the 25 G group,the DHI％ and Pfirrmann scores and the pathological score of each time at 2,4 and 6 weeks after operation in 18 G group have significant difference (P ＜ 0.05).Conclusions The middle size needle (21G) is better to induce disc degeneration.The 2-week time point may be the better time frame to further experimental treatments.