Fig. 2: CLU and fibrosis-related expression are upregulated in LFH.

a Preoperative determination of the LF thickness by MRI. The red dotted area was chosen for analyses. The red arrow denotes LF thickness at facet joint levels. b Representative LF samples obtained from non-LFH patients and LFH patients during spinal surgery. c Representative images of Masson’s trichrome and EVG staining of the LF samples from the LFH group and non-LFH group. Masson’s trichrome staining (elastic fibers are stained crimson, while collagen fibers are stained blue); EVG staining (elastic fibers are stained black, while collagen fibers are stained pink). Scale bar indicates 50 μm. d–f Immunohistochemical staining of CLU, TGF-β1 and α-SMA in LF tissues from the two groups (n = 6). The scale bar indicates 100 μm. g–i Quantitative analysis of the positive cell ratio for CLU, TGF-β1 and α-SMA. Error bars: S.D. **P < 0.01. j–l Validation of gene expression levels by RT‒PCR. The mRNA expression levels of CLU, TGF-β1 and α-SMA were markedly higher in the LFH group (n = 6) than in the non-LFH group (n = 6). Relative mRNA levels were normalized to GAPDH via the comparative Ct method. Data are expressed as the mean ± S.D. **P < 0.01. m Western blot analysis of CLU, TGF-β1, α-SMA, and COL1A2 protein expression in LF tissues from the two groups (n = 6). GAPDH was the loading control.