Korean Journal of Anatomy  2003;36(5):397-403

Reduction of Spinal Cyclooxygenase-2 with Transcutaneous Electrical Nerve Stimulation and Cold Therapy in Rats of Carrageenan-induced Inflammatory Muscle Pain.

Yun Woong PAEK 1 ; Yun Won CHAE ; Jung Woo KIM

Affiliations

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Keywords

COX-2; TENS; Cold therapy; Hyperalgesia

Country

Republic of Korea

Language

Korean

Abstract

The purpose of this study was to investigate the effects of transcutaneous electrical nerve stimulation (TENS) and cold therapy on cyclooxygenase-2 (COX-2) expression in lumbar spinal cord and on secondary hyperalgesia produced by muscle pain. Muscle pain was experimentally induced by injection of 2% carrageenan into gastrocnemius muscle of Sprague-Dawley rats. For assessment of secondary hyperalgesia, the rats were tested for paw withdrawal latency (PWL) and tail flick latency (TFL) to heat stimulus. COX-2 expression in lumbar cord was examined using RT-PCR and immunohistochemistry. Secondary hyperalgesia to heat stimulus was significantly reduced in the both TENS- and cold-treatment groups, compared to the control group. The COX-2 mRNA levels were down-regulated in the lumbar spinal cord in the both TENS- and cold-treatment groups. In addition, COX-2 immunoreactivity was decreased in the dorsal horn of the lumbar spinal cord in the both TENS- and cold-treatment groups. These results suggested that decreased COX-2 expression in the lumbar spinal cord of the subjects receiving TENS treatment and cold therapy might be an important factor for reducing secondary hyperalgesia produced by muscle pain.