Effects of dexamethasone and acetylsalicylic acid on inflammation caused by complete Freund’s adjuvant in the naked mole rat (Heterocephalus glaber)

The naked mole rat (NMR) is a fossorial rodent that has been observed to have a unique nociceptive system in comparison to others. In this study, we explored on characterization of chronic inflammation in the NMR using Complete Freund's adjuvant (CFA) and investigated the effects of dexamethasone and acetylsalicylic acid on the resulting inflammation. The NMRs were injected with 0.1 ml of CFA subcutaneously in the right hind paw, and an equivalent volume of normal saline was injected to the control group. Swelling of the injected right hind limb was observed within 24 h of injection, which involved the tibiotarsal joint, palmar surface and the digits of the injected paw. Swelling persisted for 6 weeks of experimentation and peaked between day 14 and 21. The resulting inflammation affected the mobility, stance and joint rigidity of CFA treated NMRs in comparison to the control group. Treatment of the chronic phase of the inflammation from the 11^th day with dexamethasone and acetylsalicylic acid showed no statistical significance in paw circumference compared to the control group, other than on a few, negligible occasions. The present data showed that CFA was able to induce chronic inflammation in the NMR, and the NMR could thus be established as a model for chronic inflammation. There is, however, need for more sensitive parameters to evaluate the effects of anti-inflammatory drugs.

Marham-Mafasel decrease joint inflammation and IL-1β gene expression in rheumatoid arthritis animal model

Background

Rheumatoid arthritis (RA) is a systemic chronic disease with synovial membrane, tendon and articular tissue inflammation. Current treatments of RA have many side effects and are quite expensive. Today, new treatments procedures and inexpensive herbal drugs are developed. Marham‐Mafasel is mainly made out of two traditional herbs (Arnebia euchroma and Martricaria chamomilla).

Objective

In this study, for the first time, the impact of Marham‐Mafasel on joint inflammation, histopathological changes and IL‐1β gene expression was evaluated in RA animal model.

Methods

The RA was induced by a single s.c. injection of 0.1 ml Freund's complete adjuvant into the left hind footpad. In continuous, 15 RA male Wistar rats were used in three groups: I: Control; II: Treatment I (Piroxicam) and III: Treatment II (Marham‐Mafasel). The volume of the hind paw was measured every day from 0 to 19 using water changed volume approach. The inflammation in the joint was evaluated using histopathology assay and gene expression of IL‐1β was evaluated with use of Real‐Time PCR.

Results

Hind paw swelling of Marham‐Mafasel at days 10th and 19th was reduced compared with the control group (p < 0.05). There was no statistically difference in histological degrading and changes index in three groups (p ≥ 0.05). Relative expression of IL‐1β in Marham‐Mafasel group was significantly decreased compared with other groups.

Conclusion

The co‐administration of M. Chamomile and A. euchroma, called Marham‐Mafasel, decreases IL‐1β gene expression that leads to a reduction in inflammation in rheumatoid arthritis (RA) animal model.