[Effects of manual loading on calcitonin gene-related peptide and nerve growth factor in rats with chronic low back pain].

OBJECTIVE To observe the analgesic effect of manipulation loading on chronic low back pain (CLBP) model rats and the expression of inflammatory factors in psoas major muscle tissue, and to explore the improvement of manipulation on local inflammatory microenvironment. METHODS Thirty two SPF male SD rats weighing 340-360g were randomly divided into blank group, sham operation group, chronic low back pain model group and treatment group, with 8 rats in each group. In the model group, L4-L6 lumbar vertebrae were implanted with external link fixation system (ELFS). After implantation of ELFS, the treatment group received manualintervention with 5N force and 2Hz frequency on both sides of the spine, 15 min / time, once a day, for 14 consecutive days. Paw with drawl threshold (PWT) and paw withdrawl latency (PWL) was measured before modeling and on the 1st, 3rd, 7th, 10th and 14th day after intervention. At the end of the treatment cycle, the concentrations of calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) in psoas muscle were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS There was no significant difference in PWT and PWL between the blank group and the sham operation group after modeling (P>0.05);after modeling, PWT and PWL in the CLBP model group and the treatment group were significantly decreased(P 0.05);on the 7th day after manual loading, the pain threshold value in the treatment group was higher than that in the CLBP model group, but there was no significant difference There was no significant difference between the two groups (P=0.056>0.05). On the 10th and 14th day of treatment, the mechanical pain threshold of the treatment group began to rise, and it was statistically significant compared with CLBP model rats (P 0.05);on the 7th day, the PWL of the treatment group was significantly higher than that of CLBP model group, there was statistical significance (P=0.016<0.05). Manual loading improved thermal hyperalgesia in CLBP rats until the end of the experiment. The contents of CGRP and NGF in psoas major muscle of CLBP model group were higher than those of blank group and sham operation group (P<0.01). After treatment, the contents of CGRP and NGF decreased significantly(P<0.01). CONCLUSION Local massage loading has analgesic effect on CLBP rats, at the same time, it can inhibit the content of CGRP and NGF in psoas muscle tissue of CLBP rats, and improve the local inflammatory microenvironment.