Investigation of the effects of gabapentin on the inflammatory response and gastric mucus secretion in rats

B KAYGISIZ1, FS KILIC1, S AYDIN1, A MUSMUL2, K EROL1. 1Eskisehir Osmangazi University Medical Faculty, Dept. of Pharmacology 26480, Turkey, 2Eskisehir Osmangazi University Medical Faculty, Dept. of Biostatistics 26480, Turkey

Objective: Gabapentin which is an analogue of gamma-aminobutyric acid, is used as an anticonvulsant agent. Gabapentin was also shown to be effective in the treatment of neuropathic and inflammatory pain. It was found that S (+)-3-Isobutylgaba, which is a more potent analogue of gabapentin, reduced artritis. This study aims to assess the effects of gabapentin on an inflammation model and gastric mucus secretion as well as on blood levels of interleukine-1 beta(IL-1β, tumor necrotizan factor-alpha (TNF-α) and interleukine-10 (IL-10) in rats.

Materials and Methods: Male, Spraque-Dawley rats were used (n=8 for all groups; total n=40). Gabapentin was administered at doses of 10, 30 and 100mg/kg. Saline was given to control group and diclofenac 5mg/kg was used as positive control. İnflammatory response was formed by injection of 0,1 ml of 2% formaldehyde to back left paw of each rat on the first (day 1) and third days (day 3) of the experiment to produce hind paw edema. Drugs or saline treatments were administered via gavage and started on the 4th day (day 4) and lasted for 10 days. The size of the hind paw was measured on day 1 before the induction of the inflammation, on day 4 and on the day after the termination of the treatment procedure and intracardiac blood samples were taken to evaluate cytokine levels just before the measurements of hind paw edema. Then the stomachs of each rat were removed immediately to evaluate gastric mucus secretion. Results were statistically analyzed with Kruskal-Wallis test.

Results: Gabapentin dose-dependently reduced edema % and increased edema inhibition % at all doses compared to control (p<0.001) and also reduced gastric mucus secretion as much as the reduction observed with diclofenac. Gabapentin 100mg/kg exerted a similar effect to diclophenac on the levels of IL-1β, TNF-α and IL-10 when compared in terms of groups and days.

Conclusion: We suggest that gabapentin presents antiinflammatory action. It inhibits gastric mucus secretion similar to diclofenac which is a well documented antiinflammatory agent.