OBJECTIVE

Based on the establishment of a rat model of trigger point, this study was to intervene with warm acupuncture, and to evaluate the effect on pathological morphology and pain-induced inflammation of the rat model by microscopic pathology and microdialysis.

METHODS

Sixty-four SD rats were randomly divided into group A (blank control), group B (model control) and group C (model and intervention control). Groups A and B were divided into 3 groups (A0, A1, A2 and B0, B1, B2), the group C was divided into 2 groups (C1 and C2). The MTrPs model was established in both groups B and C, warm acupuncture intervention were given to the C1 group for 7 days and the C2 group for 15 days. Rats were sacrificed in batches. MTrPs were locally sampled and stained with hematoxylin-eosin after the preparation. The pathological changes were observed under light microscopy. The iocal interleukin-1β and prostaglandin E2 were detected by microdialysis technique.

RESULTS

Microscopically, the muscle fibers of the model were arranged disorderly, broken, twisted, local fibrosis, contracture thickening and so on; macrophage and other inflammatory cell invasion in local area and a large area of adhesion occurred on the contracture nodule, the pathological state of local muscle fibers was significantly improved after warm needle intervention, local microvascular formation and maturation, local muscle fiber repair. After successful modeling, the amount of interleukin-1β and prostaglandin E2 in group B0 was significantly higher than that in group A0 before warm needle intervention (<0.01). After warming intervention for 7 days, there was no significant difference in the amount of interleukin-1β and prostaglandin E2 between group C1 and group B1 (>0.05). Group C1 and B1 were significantly higher than group A1 (<0.01); warm needle intervention for 15 days, the amount of interleukin-1β and prostaglandin E2 in group C2 were lower than those in group B2 (<0.05), but those in group C2 and B2 were significantly higher than group A2 (<0.01), and the amount of interleukin-1β and prostaglandin E2 in group C2 was lower than group C1 (<0.05).

CONCLUSIONS

The modeling method of exercise combined hitting used in this study was proved to be effective by histopathology; warm acupuncture can improve the pathological and inflammatory state of local muscle fiber in myofascial pain trigger of rat, promote local microvascular formation and maturation, and help the trigger point local muscle fiber repair.