Perhaps the most important inflammatory conditions to affect humanity are the varieties of arthritis and rheumatism diseases. Throughout the world herbal medicines appear to be widely accepted for treatment of these and many other diseases. Arthritis is a general term used for many diseases that produce either inflammation of connective tissues, particularly in joints or non-inflammatory degeneration of these tissues.
RA is an autoimmune inflammatory disease that causes pain, swelling, stiffness and loss of function in the joints. RA affects approximately 2.1 million people worldwide (and nearly about 1 percent of the United States adult population) [29
]. Current therapies have various degrees of efficacy, but toxicity frequently limits their long term use. Animal models of arthritis are normally used to help provide basic insights into autoimmune diseases and to test novel experimental approaches for the treatment of the diseases with potential anti-arthritic drugs. Some animal models of RA with a proven track record of predictability for efficacy in humans include CFA and collagen-induced arthritis in rats. These experimental models of RA induce inflammation, bone resorption, cartilage damage and pannus that resemble the human disease [30
]. Clinical or live phase parameters of body weight and paw swelling are used along with the histopathology of the joint sections to predict the efficacy of potential anti-arthritic drugs.
CFA induced arthritis is the most extensively used chronic test model in which the clinical and pathological changes are similar with those seen in human RA [31
]. Chronic inflammation in the CFA model is manifested as a progressive increase in the volume of the injected paw. It is notable that the inhibitory effect of AFCQ (100 mg/kg) on the volume of the injected paw was quite better than that of Celecoxib (50 mg/kg) and Methotrexate (0.3 mg/kg). CFA-induced polyarthritis is associated with an immune-mediated inflammatory reaction and the rats are unique in developing polyarthritis after CFA treatment [33
]. The initial reaction of edema and soft tissue thickening at the depot site in this model is caused by the irritant effect of the adjuvant, whereas the late-phase arthritis and flare in the injected foot are presumed to be immunological events [34
]. The suppression of such paw edema by a drug shows its immunosuppressive activity [35
]. In this respect also, AFCQ was found to be more effective than that of Methotrexate and Celecoxib. This reveals potent suppression of cell mediated immunity in arthritic rats by AFCQ. The experimental rats show that the treatment with AFCQ, Methotrexate and Celecoxib inhibited the arthritis associated joint changes. In addition to this, characteristic haematological alterations such as the decreased Hb level and increased erythrocyte sedimentation rate were also significantly restored by AFCQ, Methotrexate and Celecoxib treatments. It is proposed that the reduction in the Hb level during arthritis probably results either due to reduced erythropoietin level or a decreased response of the bone marrow erythropoietin and premature destruction of red blood cells. Similarly, an increase in the ESR is attributed to the accelerated formation of endogenous proteins such as fibrinogen and globulin and such a rise in ESR indicates an active but obscure disease process [36
]. Thus, the reduction in ESR and increase in Hb content brought about by AFCQ treatment further supports antiarthritic effect of AFCQ.
Anaemia is commonly noted in patients with chronic arthritis [37
]. The most common explanations for this condition are gastrointestinal blood loss due to arthritis medications and bone marrow changes in patients with inflammatory arthritis, which prevent the release of iron for incorporation into the red blood cells [38
]. In the present study, arthritic rats (group II) showed a reduced RBC count, reduced Hb levels, and an increased erythrocyte sedimentation rate (ESR). All these symptoms indicate an anaemic condition, which is observed severely in the arthritic group (group II). The AFCQ treated group (group V) and standard drugs treated group III and IV (Celecoxib and Methotrexate) showed a significant recovery from the induced anaemia as indicated by the RBC count and Hb level. WBC count is an indicator of infectious and inflammatory diseases [39
], the WBC count was increased in arthritic rats, which was significantly suppressed by the AFCQ treated group (group V) and standard drugs treated group III and IV (Celecoxib and Methotrexate), as indicated by the significant decrease in the WBC count.
C-reactive protein (CRP) is a member of the class of acute phase reactants. It rises dramatically during inflammatory processes [40
]. The level of C-reactive protein was found to be significantly reduced in the AFCQ treated group (group V) and standard drugs treated group III and IV (Celecoxib and Methotrexate). Ceruloplasmin, a protein synthesized in the liver, contains 8 atoms of copper in its structure. Free copper ions are powerful catalysts of free radical damage. By binding with copper, ceruloplasmin prevents free copper ions from catalyzing oxidative damage to liver. The arthritic rats and Methotrexate treated rats exhibited significantly elevated copper level, which was found significantly decreased in AFCQ and Celecoxib treated rats.
The observed histopathological changes of proximal tibiotarsal joints of all groups are shown in Figure 4. Group I showed the histopathology of normal ankle joint. In Group II the arthritic rat joint showed prominent abnormalities from the normal joint like edema formation, degeneration with partial erosion of the cartilage, destruction of bone marrow and extensive infiltration of inflammatory exudates in the articular surface. The standard drug treated rat joints showed normal bone marrow with less cellular infiltrates. AFCQ treatment for 14 days showed less inflammatory signs like absence of edema formation along with normal bone marrow status and less cellular infiltrates on the articular surface with less cartilage destruction. The overall prevention of the inflammatory signs of the rat ankle joints was significant in 14 days AFCQ treated group as compared with 14 days drug treated group. Degeneration of the ankle joint was not observed in any of the drug treated groups when compared with the arthritic control.
Radiographic changes in RA conditions are useful diagnostic measures which indicate the severity of the disease. Soft tissue swelling is the earlier radiographic sign, whereas prominent radiographic changes like bony erosions and narrowing of joint spaces can be observed only in arthritis [41
]. The radiographic features of the rat joints in CFA induced arthritic model are shown in Figure 5. In CFA induced arthritic rat (group II), soft tissue swelling along with narrowing of the joint spaces were observed which implies the bony destruction in arthritic condition. In standard drug Celecoxib and Methotrexate treated groups the bony destruction was found to be prevented and also there was a negligible swelling of the joints. Similar to the histopathological studies, AFCQ treatment for 14 days has shown significant prevention against bony destruction by showing less soft tissue swelling and preventing the dissolution of bone when compared with arthritic groups.
Treatment of a disease like arthritis is expected to address the alterations in the multiple mediators and/or their effects to derive clinical benefits due to medication. As evident from the results of experiments presented in this paper, Cissus quadrangularis
possesses anti-inflammatory and anti arthritic activity and the effects of AFCQ may be due to active constituents like phenolics present in it.