Anti inflammatory effect of thymoquinone in comparison with methotrexate on pristane induced arthritis in rats

To determine the anti-inflammatory effects of thymoquinone on body weight, clinical score of inflammation, total leukocyte count and differential leukocyte count in arthritic rats and compare it with that of methotrexate.

The study was conducted at the Post-Graduate Medical Institute, Lahore, from March to September 2013, and comprised female Sprague-Dawley rats randomised into four equal groups; group A (healthy control), group B (positive control), group C (thymoquinone treated) and group D (methotrexate treated). Arthritis developed in Group B, C and D within two weeks after a single intra-dermal injection of pristane. Body-weight measured on electronic balance in grams and clinical score of inflammation scored on macroscopic scoring system were monitored on every alternate day while total leukocyte count and differential leukocyte count were taken at day 0, 16 and 30. After day 15, groups A and B were given 0.5ml of distilled water by intra-peritoneal injection daily for 15 consecutive days; group C was given thymoquinone 2mg/kg by intra-peritoneal injection daily for 15 consecutive days, and group D received methotrexate 0.5mg/kg by intra-peritoneal injection, daily for 15 consecutive days. SPSS 20 was used for statistical analysis.

The 32 rats in the study were randomised into four groups of 8(25%) each. In group A the body-weight continued to increase and reached a mean of 144.13±10.8% of the baseline at day 30. In group B the weight reduced to 93.13±4.19% at day 16 and to 88.3±6.97% at day 30. In groups C and D the weight reduced to 87.25±7.69% and 88.5±7.07% respectively at day 16; then the animals in the two groups regained their weight which increased to 108.63±10.89% and 103.38±6.25% respectively at day 30. The score was zero in group A throughout the study period. The score of group B, which was zero at day 0, reached a mean of 16±0 at day 16. In groups C and D, the mean score increased till day 16 and reached 16±1 and 16±0 respectively, and then reduced to 5±2 and 4±1 at day 30 respectively.

Evaluation of data supported the anti-inflammatory activities of thymoquinone, so it may be investigated as an effective anti-inflammatory drug in rheumatoid arthritis.