The Role of G Protein-coupled Receptor Kinase 2 in Diabetic Mechanical Hyperalgesia in Rats.

Xu, Xiu-Hua; Du, Rui-Qin; Li, Lin; Yang, Lin-Lin; Zhang, Yi; Li, Quan-Min

BACKGROUND Previous studies have indicated a negative correlation between GRK2 expression and pain development and transmission. Here, we investigated whether G protein-coupled receptor kinase 2 (GRK2) was involved in regulating diabetic mechanical hyperalgesia (DMH). METHODS The adeno-associated viral vectors containing the GRK2 gene (AAV-GRK2) were used to upregulate GRK2 protein expression. The expression of GRK2 and exchange protein directly activated by cyclic adenosine monophosphate 1 (Epac1) in the dorsal root ganglion (DRG) of lumbar 4-6 was detected via immunoblotting and immunohistochemistry, and the transfection of the GRK2 gene was detected by immunofluorescence. RESULTS Low levels of GRK2 were able to sustain STZ-induced pain in DMH rats. Intrathecal injection of AAV-GRK2 vector upregulated GRK2 expression, providing pain rain to rats with DMH. With an increase in DMH duration, there was a decrease in paw withdrawal threshold (PWT) value, aggravating the pain, resulting in a decreasing pattern in GRK2 protein expression over time, whereas Epac1 protein expression showed an opposite trend. CONCLUSION GRK2 expression regulated DMH progression and is expected to play a role in the development of targeted therapy for DMH. GRK2 and Epac1 expressions play a vital role in maintaining pain in DMH rats.