Abirritation of Discogenic Pain Model in SD Rats by Paravertebral Ozone Injection / 中山大学学报(医学科学版)

ABSTRACT

@#【Objective】To investigate the analgesic and degenerated regularity of paravertebral ozone injection in the discogenic pain model of SD rats ，and to reveal the mechanism of analgesic effect of ozone preliminarily.【Methods】 Male SD rats（n = 65）were randomly divided into control group（n = 15），model group（n = 25）and ozone group（n = 25）. The L5- 6 intervertebral discs of SD rats in model group and ozone group were punctured to establish discogenic pain models. Ozone was injected paravertebrally in ozone group rats on the 22nd day after modeling. The rats in control group were normal. A quantitative allodynia assessment technique and MRI were used to detect the 50% mechanical withdrawal threshold（50%MWT）and Pfirrmann grade of L5-6 intervertebral discs at different time intervals. The expression of tumor necrosis factor-α（TNF- α）and calcitonin gene-related peptide（CGRP）in left dorsal root ganglion and sciatic nerve were detected by western blot.【Results】The 50% MWT of both hind paws were different from each other in three groups at each time after the 22nd day after modeling（P < 0.05）. In the ozone group，the 50% MWT rose on the 22nd day after modeling（left 7.6±6.8，right 3.6±1.0，P < 0.05 vs pre-ozone injection），and reached the peak on the 24th day after modeling（left 10.6±8.2，right 7.9±6.7，P < 0.05 vs pre-ozone injection），and maintained this level until the 56th day after molding. In the ozone group，the L5-6 intervertebral disc degeneration was apparently visible compared with model group（P < 0.05）. The expression of TNF- α and CGRP in dorsal root ganglion and sciatic nerve were different from each other in three groups（model>ozone>control，P < 0.05）.【conclusions】Paravertebral ozone injection can alleviate the pain of discogenic pain model rats，but aggravates the degeneration of the lumbar disc. Paravertebral ozone injection can reduce the expression of TNF-α and CGRP in the sciatic nerve and dorsal root ganglia of discogenic pain model rats.