Comparative evaluation of various analgesic drugs in Wistar rats used as a teaching tool to teach animal experiments to post graduate MD Pharmacology students

Mirza Atif Beg, Shakti Bala Dutta, Hitender Kumar, Amandeep Singh, Shalu Bawa



Background: Postgraduates when join Pharmacology department, they don’t have much idea about guidelines and methods to do animal experiments. This study was designed to sensitize postgraduate students to animal experiments by evaluating the anti-inflammatory effects and the efficacy of diclofenac, tramadol and etoricoxib in reducing paw edema in wistar rats.

Methods: The wistar rats of 225-250gram were divided into four groups (n=10 each). In all the groups the paw edema on right paw was created using 0.1ml of 1% formalin subcutaneously. Group 1 rats (control), group 2 were given diclofenac, group 3 were given tramadol and group 4 were given etoricoxib orally. The parameters assessed were water displacement in plethysmography after 2, 4, 24, 48 hours of giving the drug. The circumference of edematous paws after 4 hours, licking of paw was observed over 30minutes of giving the drug and was compared. Pre and post study feedback were obtained from the students by using a preformed questionnaire to assess the knowledge gained by the students.

Results: The test showed that all the drugs were effective in reducing inflammation, circumference of edema and the licking duration significantly (p<0.05). The post study answering of questions by postgraduate was 100% in comparison to pre-study answering which was 33%.

Conclusions: A short animal study conducted as a teaching tool to postgraduate students was able to teach the guidelines of animal experiments and handling of animals effectively.


Paw edema, Paw licking, Plethysmograph

Full Text:



Coderre TJ, Vaccarino AL, Melzack R. Central nervous system plasticity in the tonic pain response to subcutaneous formalin injection. Brain Res. 1990 Dec 3;535(1):155-8.

Schmidt KL, Ott VR, Rocher G, Schaller H. Heat and cold inflammation. J Rheumatol. 1979;38:827-36.

Hong Y, Abbott FV. Behavioural effects of intraplantar injection of inflammatory mediators in the rat. Neuroscience. 1994 Dec 1;63(3):827-36.

Tjølsen A, Berge OG, Hunskaar S, Rosland JH, Hole K. The formalin test: an evaluation of the method. Pain. 1992 Oct 1;51(1):5-17.

Robbins SL, Cotran RS, Kumar V. Pathologic basis of disease. 5th ed. Philadelphia. W.B. Saunders Company.1994:53-75.

Piovezan AP, D'Orleans-Juste P, Tonussi CR, Rae GA. Endothelins potentiate formalin-induced nociception and paw edema in mice. Canadian J Physiol Pharmacol. 1997 Jun 1;75(6):596-600.

Doak GJ, Sawynok J. Formalin-induced nociceptive behavior and edema: involvement of multiple peripheral 5-hydroxytryptamine receptor subtypes. Neuroscience. 1997 Jul 28;80(3):939-49.

Rodrigues AJ, Kamath L. Guinea pig versus computer mouse in post graduate practical pharmacology. International J Basic Clin Pharmacol. 2017 Jan 28;6(2):441-4.

Dikshit RK. Postgraduate education in medical pharmacology. Indian J Pharmacol. 2007 Jul 1;39(4):171.

Page RC. The etiology and pathogenesis of periodontitis. Compend Contin Educ Dent. 2002;23:11-4.

Lee IO, Jeong YS. Effects of different concentrations of formalin on paw edema and pain behaviors in rats. J Korean Med Sci. 2002 Feb;17(1):81.

Azoubel MC, Menezes AM, Bezerra D, Oriá RB, Ribeiro RA, Brito GA. Comparison of etoricoxib and indomethacin for the treatment of experimental periodontitis in rats. Brazilian J Med Biol Res. 2007 Jan;40(1):117-25.

Khandale M, Magadum SB, Limaye RP. The study of anti-inflammatory activity of buspirone in rats. Int J Healthcare Biomed Res. 2015;4(1):51-9.

Naidu G, Konda VG, Ramana V. Comparative study of anti-inflammatory activity of newer macrolides with etoricoxib. J Evolution Med Dental Sci. 2014 Apr 3(4):2413-9.