[Analysis of the effect of midazolam on pain in a rat model of lumbar disc herniation based on the p38 MAPK signaling pathway].

Objective: To investigate the effect of midazolam on pain in lumbar disc herniation model rats based on p38 MAPK signaling pathway.

Methods: Fifty SPF-grade Sprague-Dawley healthy rats, half male and half female, were selected and randomly divided into normal group, model group, and low-dose, medium-dose, high-dose groups. Model group and low-dose, medium-dose, high-dose groups were initially modeled for lumbar disc herniation. Intraperitoneal injection of saline was performed in rats of normal and model groups; and in the low-dose, medium-dose, and high-dose groups, intraperitoneal injection of midazolam was performed with doses of 30, 60, and 90 mg/kg, respectively. Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), 5-hydroxytryptamine (5-HT), β-endorphin (β-EP), substance P (SP), neuropeptide Y (NPY) were detected in the serum of rats by enzyme-linked immunoassay. The expression of p38 MAPK and matrix metalloproteinase-3(MMP-3) protein were detected by Western blot in the tissues of rats of each group.

Results: The levels of TNF-α, IL-1β and β-EP were higher and the level of 5-HT was lower in the model group than in the normal group(<0.05);the levels of TNF-α, IL-1β and β-EP were lower and the level of 5-HT was higher in the low-dose, medium-dose and high-dose groups than in the model group(<0.05). The levels of SP and NPY increased in the model group compared with the normal group (<0.05) and the levels of SP and NPY decreased in the low-dose, medium-dose and high-dose groups compared with the model group (<0.05). The expression of p38 MAPK and MMP-3 increased in the model group compared with the normal group (<0.05); the expression of p38 MAPK and MMP-3 decreased in the low-dose, medium-dose and high-dose compared with the model group(<0.05).

Conclusion: Midazolam may ameliorate the immune inflammatory response in rats with a model of lumbar disc herniation, possibly regulated through the p38MAPK signaling pathway.