Gabapentin effectively alleviates pain sensitization and regulates CACNA2D1 expression in postherpetic neuralgia rats / 中国药理学通报

ABSTRACT

Aim To identify the molecular target of gabapentin in the treatment of postherpetic neuralgia(PHN). Methods The molecular target of gabapentin for PHN was analyzed by network pharmacology and molecular docking and confirmed by coprecipitation test. Rats were randomly divided into control group, model group, model+50 mg·kg-1 gabapentin group, model+100 mg·kg-1 gabapentin group, and model+200 mg·kg-1 gabapentin group, with nine rats in each group. The pain-related behaviors of the rats were measured at different time points. The mRNA and protein expressions of CACNA2D1, Bax, and Bcl-2 in rat spinal cord were determined by immunofluorescence, Western blot, and qPCR. Results CACNA2D1 was the target gene of gabapentin that determined via network pharmacology, molecular docking, and co-precipitation tests. After modeling, mechanical pain threshold and thermal pain threshold significantly decreased, and the number of apoptotic GABA cells significantly increased. However, after intraperitoneal injection of 50, 100, and 200 mg·kg-1 gabapentin, mechanical pain threshold and thermal pain threshold significantly increased(P<0.05), and the number of apoptotic GABA cells significantly decreased(P<0.01). Immunofluorescence and Western blot results showed that compared with the model group, with the increase of gabapentin concentration, the positive expression rate of Bax significantly decreased, and the positive expression rate of Bcl-2 and CACNA2D1 significantly increased. The mRNA expression levels of Bax, Bcl-2 and CACNA2D1 detected by qPCR were consistent with the results of immunofluorescence and Western blot. Conclusions Gabapentin up-regulates the expression of target protein CACNA2D1, inhibits the proapoptotic protein Bax, and promotes the expression of apoptotic inhibitor Bcl-2.