Intervertebral Disc Degeneration Induced by Needle Puncture and Ovariectomy: A Rat Coccygeal Model

Abstract

Objectives. To establish a novel animal model of intervertebral disc degeneration (IVDD) in rats and to investigate the effect of 17β-estradiol (E2) intervention in this model. Methods. This study was divided into two parts: animal model (four groups: Sham, ovariectomy (OVX), Puncture, and OVX+Puncture; three-time points: 4, 8, and 12 weeks; three female rats/group/time point) and drug intervention (Sham, OVX+Puncture+corn oil, and OVX+Puncture+E2; three female rats/group). The rats were analyzed by micromagnetic resonance imaging (MRI), hematoxylin and eosin (HE) staining, and safranin-O staining. Results. MRI and histological scores significantly differed among the four groups at the three-time points (all $P<0.05$ ). IVDD progressed with time in the OVX, Puncture, and OVX+Puncture groups (all $P<0.05$ ). The changes were the most obvious in the OVX+Puncture group. In the E2 intervention part, the Veh group had the worst MRI signals and histological scores ( $P<0.05$ ). The MRI scores in the E2 group were less obvious compared to the Sham group ( $P>0.05$ ). Also, the histological scores were significantly different between the Sham and E2 groups ( $P<0.05$ ). Conclusions. The combination of ovariectomy and needle puncture can synergically induce IVDD in rat coccygeal discs. Estrogen treatment can effectively ameliorate IVDD progression in the newly established IVDD models.