Authors: Haroon ur Rasheed , Kauser Ismail , Muhammad Owais Ismail , Akhtar Ali , Humaira Arif , Syeda Zehra Ahmed

Abstract

Background and Objective: Conventional disease-modifying anti-rheumatic drugs used for the treatment of rheumatoid arthritis are
known for their steady onset of action and multiple adverse effects. The objective of this study was to evaluate the anti-arthritic activity of the ethanolic extract of Solanum nigrum (SN) in the Complete Freund’s adjuvant-induced arthritic rat model.

Methods: A total of 30 male Wistar albino rats were used in a 4-week pre-clinical experimental study. The animals were divided into
5 groups; Group-I negative (healthy) control (0.9% normal saline), Group-II positive (diseased) control (0.9% normal saline), Group-III
standard group (Methotrexate 1.5 mg/kg), Group-IV (SN 100 mg/kg), and Group-V (SN 200 mg/kg). To develop arthritis, 0.1ml of Complete Freund’s Adjuvant was administered intraarticularly in the right knee joints of all groups except Group-I at day 0. Knee joint circumference was assessed by using a Vernier caliper once weekly for 4 weeks. For euthanasia, 100 mg/kg pentobarbital was injected intraperitoneally in all animals on the 29th day for the assessment of histopathological changes in the knee joints. SPSS version 22 was used to analyze the results, and ANOVA was applied for intergroup and intragroup comparisons.

Results: Edema in the positive controls (group-II) increased continuously throughout the study duration. While group-III methotrexate
(MTX) showed an initial increase in edema, but slight reduction was observed in the last two weeks. Group-V (SN200) with a higher dose of herbal extract showed maximum reduction in edema. Histological assessment showed the maximum arthritic score (3) in group-II. While 66% of animals in group-III MTX and group-IV (SN100) showed mild scoring exhibiting scattered inflammatory cells, Group-V showed maximum improvement in the histopathological changes, and 66% of animals showed normal scoring, while 33% animals showed few inflammatory cells (p < 0.05).

Conclusion: Ethanolic extract of SN demonstrated decreased knee joint edema and improved histopathological outcomes in animal model, suggesting therapeutic potential for arthritis management in humans, in future. 

Keywords: Arthritis, Rheumatoid arthritis Histology, Edema, Solanum nigrum.