Establishment of a New Rat Model of Lumbar Disc Herniation for Minimally Invasive Interventional Surgery

The objective of this study was to establish a new rat model of lumbar disc herniation for minimally invasive interventional surgery. Sixty Sprague Dawley rats were selected and randomly divided into three groups of 20 in each group, group A the new model group, group B model control group and group C the sham operation group. Group A sample was taken from the nucleus pulposus of the caudal vertebra and transplanted to the root of the sciatic nerve. The group B sample was taken from the nucleus pulposus of the caudal vertebra and transplanted to the L5 spinal nerve side to establish a model. The C group was only sutured after the sciatic nerve was separated, and no other treatment was performed. The mechanical pain threshold and thermal pain threshold were measured before and after 1, 3, 5, 7 and 14 days of operation, and the lower limb temperature was measured. Half of the rats in each group were sacrificed on the day 7 and 14 after operation. The expression levels of IL-8 and TNF-α were detected by immunohistochemistry in the L5 dorsal root ganglia and sciatic nerve tissues. The results showed that compared with group C, group A and group B had lower mechanical pain threshold and thermal pain threshold at 1, 3, 5, 7 and 14 days after operation and lower average limb temperature. The number of IL-8 and TNF-α positive cells in L5 dorsal root ganglia and sciatic nerve tissue increased at 7 days after operation. The number of positive cells decreased at 14 days, but it was still higher than that of group C. The difference between the two groups was significant (p>0.05); compared with group B, the mechanical pain threshold and thermal pain threshold and the temperature of lower limbs of group A tend to be consistent at 1, 3, 5, 7, and 14 d after operation, and the number of IL-8 and TNF-α positive cells tends to be consistent. There is no significant difference between the two groups (p<0.05). It could be concluded that the new rat model of lumbar disc herniation in this experiment can perfectly replicate the etiology of lumbar disc herniation. The procedure is simple and the injury is small. It provides a favorable and stable experimental model for further study of the mechanism and treatment of lumbar disc herniation in the future.