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. 2021 Jan 12;11:638. doi: 10.1038/s41598-020-79958-9

Figure 2.

Figure 2

UPAL gel inhibits tumour necrosis factor alpha (TNF-α) production in rat and rabbit intervertebral disc (IVD) degeneration models. The rat nucleus pulposus (NP) punch (ad) and rabbit NP aspiration (eh) models were used for immunohistochemical (IHC) analysis to detect the TNF-α levels 1, 4, 7, and 28 days after surgery. The number of TNF-α-positive cells in each staining was calculated as a percentage of the number of total NP or annulus fibrosus (AF) cells in five independent, randomly selected fields per disc. TNF-α-positive cells are stained red, and nuclei was stained purple. (a) Representative image of TNF-α-positive NP cells in the rat model (allows). Scale bar, 50 µm. (b) Representative IHC staining for TNF-α 1, 4, 7, and 28 days after surgery in rat NP and AF tissues. Arrows indicate TNF-α-positive cells. Scale bar, 100 µm. Percentage of TNF-α-positive cells in rat NP tissue (c) and AF tissue (d). (e) Representative image of TNF-α-positive NP cells in the rabbit model (arrows). Scale bar, 50 µm. (f) Representative IHC staining for TNF-α 1, 4, 7, and 28 days after surgery in the rabbit NP and AF tissues. Arrows indicate TNF-α-positive cells. Scale bar, 100 µm. Percentage of TNF-α positive cells in rabbit NP tissue (g) and AF tissue (h). The percentages of TNF-α-positive NP and AF cells in the gel group were significantly lower than those in the punch or aspiration group at each time point in the rat or rabbit model, respectively (*P < 0.05). The boxes represent the median and the interquartile range, with the vertical lines showing the range. The rhombus shape represents the 95% confidence interval (at each time point, n = 3 rats; n = 6 IVDs in each group).