Methanol extract of smokeless tobacco alters inflammation and nociception process in animal models

摘要

Purpose: To investigate the inflammatory and nociceptive alterations due to the use of Nicotiana tabacum or smokeless tobacco (MEST) owing to the fact that it is used by some people to relieve dental pain. Methods: Hepatic biochemical indicators and thiobarbituric acid reactive substances assay were used to assess MEST toxicity and pharmacological doses selection. The effects on inflammation of different pharmacological doses (100, 200 and 500 mg/kg i.p.) of MEST were evaluated using xylene-induced ear edema and cotton pellet granuloma tests. Indomethacin (10 mg/kg, i.p.) was used as positive standard drug, whereas the vehicle 0.5 % CMC treated group was considered as negative control. Acetic acid-induced abdominal contraction test and formalin-induced hind paw licking model were utilized to assess the role of MEST in nociception. Indomethacin (10 mg/kg i.p.) and diclofenac sodium (10 mg/kg i.p.) were used as positives standard drugs. The vehicle used was 0.5% CMC which served as the negative control. Results: MEST (50 %, 200 mg/kg) and indomethacin (47.5 %) both elicited a significant (p 0.001) anti-edematogenic effect on xylene-induced ear edema. MEST also showed a significant (p 0.001) inhibitory effect on granuloma formation at all administered doses as compared to the untreated groups which was comparable to standard drug indomethacin. The number of acetic acid induced writhings was observed to be significantly increased (p 0.001) by MEST at all doses, unlike diclofenac that led to significant reduction (p 0.001) in the number of writhings, when compared to the untreated group. MEST also showed a significant (p 0.05) dose-dependent reduction of the hind paw licking caused by formalin when compared to the vehicle control. Conclusion: These results signify that administration of MEST induces inflammatory and nociceptive alterations. However, the extract is not recommended for dental pain due to its other toxic effects that have previously been reported.