Anti-Inflammatory Drug Tests

Anti-Inflammatory Drug Tests The method described by Lorke with slight modification was used to determine the safety of the MEA. Briefly, normal healthy male mice were divided into groups of five mice in each cage. MEA (100 and 1000 mg/kg) or vehicle were intraperitoneally administered. Access to food and water, toxic symptoms and the general behavior of mice were observed continuously for 1 h after the treatment, intermittently for 4 h, and thereafter over a period of 24 h. The mice were further observed for up to 14 days following treatment for any signs of toxicity and mortality. Result Over the study duration of 14 days, there were no deaths recorded in the groups of mice given 100 or 1000 mg/kg IP of MEA. During the observation period, MEA administration did not induce any variations in the general appearance or toxic signs in the animals. The writhing test has long been used as a screening tool for the assessment of analgesic or anti-inflammatory properties of new substances (Collier et al., 1968). This m ethod presents a good sensitivity, although it has poor specificity. To avoid misinterpretation of the results, in the present study the antinociceptive effects of MEA were confirmed in the formalin test, a model of inflammatory pain which has two distinctive phases which may indicate different types of pain (Hunskaar and Hole, 1987). The early and late phases of formalin test have obvious differential properties, and therefore this test is useful not only for assessing the analgesic substances, but also for elucidating the mechanism of analgesia (Shibata et al., 1989). The early phase,  named non-inflammatory pain, is a result of direct stimulation of nociceptors and reflects centrally-mediated pain; the late phase,  named inflammatory pain, is caused by local inflammation with a release of inflammatory and hyperalgesic mediators (Hunskaar  and Hole, 1987). The thermal model of the tail-flick test is considered to be a spinal reflex, but could also involve higher neural struc tures, and therefore this method identifies mainly central analgesics (Jensen and Yaksh, 1986; Le Bars et al., 2001). Due to their implication in virtually all human and animal diseases, inflammation and pain have become the focus of global scientific research. Adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs) and opioids have necessitated the search for new drugs with minimal side effects (Dharmasiri et al.,2003; Vittalrao et al., 2011). The current trend of research is the investigation of medicines of plant origin because of their affordability and accessibility with minimal side effects. The thermal model of the tail-flick test is considered to be a spinal reflex, but could also involve higher neural structures, and therefore this method identifies mainly central analgesics (Jensen and Yaksh, 1986; Le Bars et al., 2001). The analgesic activity of Cyathula prostrata in this study was investigated using the hot plate and mouse writhing tests. The hot plate test is useful for the evaluation of centrally acting analgesics which are known to elevate the pain threshold of mice towards  heat (Hiruma-Lima et al., 2000). It also indicates narcotic involvement with opioid receptor (Turner, 1965). The writhing model is a sensitive method for screening peripheral analgesic efficacy agents and it is more sensitive to non-steroidal analgesics (Collier et al., 1963). The analgesic effect of acetic acid is due to the liberation and increased level of several mediators such as histamine and serotonin which act by stimulation of peripheral nociceptive neurons (Cui et al., 2010).