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

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.