Study on Hippo pathway of different period disc degeneration in rat coccygeal vertebra disc

English Keywords:Hippo  Yes-associated protein  Intervertebral disc degeneration  Animal model  Bioremediation

English Abstract:

  【Abstract】 Objectives: To observe the changes in the expression of Hippo signaling pathway during the coccygeal vertebra disc degeneration induced by annulus fibrosis puncture in rats. Methods: 60 male SD rats, were randomly divided into three groups, 20 rats without annulus puncture were used as control group(group A); 40 rats performed annulus puncture to construct intervertebral disc degeneration(IDD) model, 4 weeks after operation(group B, n=20) and 3 months after operation(group C, n=20) as the experimental groups. The IDD conditions were accessed by X-ray, MRI and HE staining. Yes-associated protein(YAP), phosphorylat Yes-associated protein(p-YAP) and cysteine-rich angiogenic inducer 61(CYR61) were detected by immunohistochemical staining to analyze Hippo signal expression in different period IDD. Results: Compared with group A, group B and C were loss disc height obviously after annulus fibrosus puncture and MRI T2 gray-value increased(P＜0.05), thus showed that IDD had been made. And when compared with group A(2.44±0.17), group B and C IDD pathological grading score(4.33±0.23, 4.22±0.22) increased significantly(P<0.05). Immunohistochemistry and Western blot analysis showed that the p-YAP expression was relatively reduced in group B(0.33±0.02) compare with group A(0.56±0.05). There was a significant difference in p-YAP expression between B and C groups(0.33±0.02 vs 0.99±0.11, P<0.05), but there was no significant difference between group B and A(P>0.05). The expression of YAP in group B was significantly higher, but it decreased significantly(P<0.05) in group C. However, the expression of target gene CYR61 was decreased in group B and there was no statistically difference compared with the group C(P＞0.05), which was not consistent with the expression of YAP. Conclusions: Hippo pathway is involved in the development of IDD in different period and plays an important role in the maintenance of intervertebral disc homeostasis.