Naringin Inhibits Apoptosis Induced by Cyclic Stretch in Rat Annular Cells and Partially Attenuates Disc Degeneration by Inhibiting the ROS/NF-κB Pathway

Figure 5

Effect of naringin on rat lumbar intervertebral disc degeneration (IVDD). (a) Representative sagittal MRI scans of the rat lumbar spine. Degenerative discs show the lost distinction of NP and AF, decreased collapsed disc space, hypointense on T2 images (“black holes”). Intervertebral discs are marked by arrows. (b) Pfirrmann grade indicating the degree of IVDD in the rat study groups. compared to the sham group. ^# compared to the IVDD group. (c, d) Representative hematoxylin and eosin staining images and degeneration grade in the intervertebral discs. Degenerative discs showed moderately to severely serpentine appearance with rupture or reversed contour or were indistinct (arrows). Scale bar: 1 mm. (e, f) Typical TUNEL staining (red) images of the rat lumbar spine demonstrating the apoptosis rate. compared to the sham group. ^## compared to the IVDD group. Scale bar: 50 μm. (g) Type I collagen expression in the intervertebral disc of rats from the naringin treatment groups increased compared with that of rats from the sham group, but decreased compared with that of rats from the IVDD group. Type I collagen-positive staining was shown in brown in ECM (arrows). Scale bar: 1 mm (disc) and 200 μm (NP and AF). (h) MMP-3 expression in the intervertebral disc of rats from the naringin treatment groups increased compared with that of rats from the sham group, but decreased compared with that of rats from the IVDD group. MMP-3-positive staining was shown in brown in ECM (arrows). Scale bar: 1 mm (disc) and 200 μm (NP and AF). AF: annulus fibrosus; NP: nucleus pulposus; ECM: extracellular matrix.

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