ABSTRACT
BACKGROUND: The combined action of mechanical compression, inflammatory factors, and matrix metalloproteinases leads to intervertebral disc degeneration. Rhizoma drynaria flavones have been shown to have anti-inflammatory effect. However, its protective effects against degeneration of the intervertebral discs remain unclear. OBJECTIVE: To investigate the potential molecular mechanisms underlying the protective effects of rhizoma drynaria flavones in a rat model of cervical intervertebral discs degeneration and analyze the clinical value. METHODS: Fifty Sprague-Dawley rats (half male and half female) were randomly divided into two groups: 10 in sham-operated group and 40 in degeneration group. Animal models of cervical intervertebral discs degeneration due to dynamic and static imbalance were made in the degeneration group. After successful modeling, 36 model rats were randomized into model group, high-dose group, middle-dose group and low-dose group (n=9 per group). Rats in the sham and model groups were intragastrically given 4 mL of normal saline per day, and those in the high-, middle- and low-dose groups were given 62.5, 125, and 250 mg/kg rhizoma drynaria solution, respectively. The C3-4, C4-5, C5-6, and C6-7 segments of the rat spine were taken. Immunohistochemistry and ELISA were used to detect expression of tumor necrosis factor α and matrix metalloproteinase 3 proteins. Quantitative RT-PCR was used to determine the mRNA expression of tumor necrosis factor α and matrix metalloproteinase 3. Western blot was used to detect the phosphorylation of IkBα. RESULTS AND CONCLUSION: Results from the immunohistochemistry, western blot, and RT-PCR, and ELISA showed that the phosphorylation of IkBα and expression of tumor necrosis factor α and matrix metalloproteinase 3 were significantly higher in the model group than the sham group (P < 0.01). However, interventions with rhizoma drynaria flavones, especially with low-dose rhizoma drynaria flavones, significantly lowered the phosphorylation of IkBα and expression of tumor necrosis factor α and matrix metalloproteinase 3. To conclude, high-, middle- and low-dose rhizoma drynaria flavones can exert protective effects against degeneration of the intervertebral discs by suppressing the nuclear factor-κB pathway and inhibiting the expressions of tumor necrosis factor α and matrix metalloproteinase 3. And low-dose rhizoma drynariae flavonoids have the optimal outcomes.