Continuous SGB Inhibits Occurrence and Maintenance of Mechanical Hyperalgesia via Reducing Inflammatory Cytokines in Striatum and PAG of PD Nociception Rat Models.

Abstract

To investigate the effect of stellate ganglion block (SGB) on nociception in Parkinson's disease (PD) rat models, and to clarify the associated mechanism. To generate PD nociception rat model 6-hydroxydopamine (6-OHDA) injection method was used. Paw withdrawal threshold (PWT) and paw retraction latency (PWL) was used to reflect mechanical stimulation and thermal stimulation, respectively, at pre-modeling and 1, 2, 3, 4 weeks post modeling. The preventive and therapeutic effects of SGB treatment on nociception were observed in Naive, Vehicle, and 6-OHDA group (model). Levels of IL-1β, IL-6, and TNF-α in striatum and periaqueductal gray (PAG) were detected with ELISA. 6-OHDA injection induced obvious reduction of bilateral PWT from 2 to 4 weeks post modeling, suggesting that PD nociception rat model was successfully established. Continuous SGB prevention inhibited mechanical hyperalgesia at 2, 3 and 4 weeks post modeling, and significantly reversed mechanical hyperalgesia at 3 and 4 weeks post modeling, compared with those of Saline group (p < 0.05). These results suggest that continuous SGB could effectively prevent and alleviate pain of PD rats. SGB treatment remarkably suppressed levels of inflammatory factors (IL-1 β, IL-6, and TNF-α) in striatum and PAG of PD rats compared with those of rats in Vehicle group (p < 0.05). Continuous SGB effectively inhibited and reversed mechanical hyperalgesia of PD nociception rats through inhibiting inflammatory response in striatum and PAG.