FIG. 1.

(A) H/E staining of NP sections of healthy and degenerated rat intervertebral disc. NPCs were sparse in healthy NP with vacuoles inside, which disappeared during senescence. In the degenerated NP, loosened NP tissues were replaced by fibrous tissues and the remaining NPCs reunited into several cell masses. (B, C) Immunofluorescent and immunohistochemical staining of healthy and degenerated rat intervertebral discs. ASIC1a expression increased in the degenerated disc. (D, E) Western blot analysis and quantitative RT-PCR of ASIC1a. Compared with the healthy NP, ASIC1a expression was significantly higher in degenerated NP. **p < 0.01. NPCs, nucleus pulposus cells.