Background and Purpose: Peripheral nerve block is often used to relieve postoperative pain. But the effect of nerve block on inflammatory response is not fully understood. Spinal cord is the primary center of pain processing. This study is to investigate the effect of single sciatic nerve block on the inflammatory response of the spinal cord in rats with plantar incision and the combined effect with flurbiprofen.
Methods: The plantar incision was used to establish a postoperative pain model. Single sciatic nerve block, intravenous flurbiprofen or the combination of both were used for intervention. The sensory and motor functions after nerve block and incision were evaluated. The changes of IL-1β, IL-6, TNF-α, microglia and astrocytes in the spinal cord were examined by qPCR and immunofluorescence respectively.
Results: Sciatic nerve block with 0.5% ropivacaine in rats induced sensory block for 2h and motor block for 1.5h. In the rats with plantar incision, the single sciatic nerve block did not alleviate postoperative pain or inhibit the activation of spinal microglia and astrocytes, but the levels of IL-1β and IL-6 in spinal cord were decreased when the nerve block wore off. The combined effect of a single sciatic nerve block and intravenous flurbiprofen not only decreased the levels of IL-1β, IL-6, and TNF-α, but also relieved the pain and alleviated the activation of microglia and astrocytes.
Conclusion: The single sciatic nerve block cannot improve postoperative pain or inhibit the activation of spinal cord glial cells, but can reduce the expression of spinal inflammatory factors. Nerve block combined with flurbiprofen can inhibit spinal cord inflammation and improve postoperative pain. This study provides a reference for rational clinical application of nerve block.
Keywords: sciatic nerve block, inflammatory response, spinal cord, flurbiprofen, plantar incision, postoperative pain