Measurement of Inflammatory Edema in Skin - Essay Example

The measurement of inflammatory oedema in skin. Interaction of mediators. Released microvascular permeability and vasodilators in the microcirculation. Introduction The thesaurus of Medical Subject Headings determines the inflammation as "a pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions" (2006). Since Galen's time this phenomenon attracts the attention of physicians and scientists. The inflammation seems to be the universal body's response to injury. It could be local or generalized, can protect our organism from harmful environmental impacts and can destroy tissues and their functions. The inflammations can be acute when all manifestations of the disease occur in short time, but there are many chronic conditions that requires prolonged treatment and rehabilitation. The PubMed database contains more than 80,000 references related to the problem of the inflammation in medicine and biology. Nevertheless, the studies dedicated to the problem of inflammatory response do not loose their pertinence and keep top positions on the ranking of the most important scientific directions. The physiology of inflammation is very complicate. There are five universal hallmarks of the inflammation, four of theme were described by Celsus in the Ancient Rome as follows tetrad: rubor (i.e. hyperemia or redness due to increased blood flow), calor (heat due to increased metabolic activity and blood flow), tumor (i.e. swelling or oedema), and dolor (i.e. pain). The fifth hallmark of the inflammation was added to the previous by Dr. Rudolf Virhow only in the middle of XIX century. This is "functio laesa" or loss of function. But these visible indices of the inflammation are the result of the sophisticated processes mediated by the numerous humoral and cellular factors (Ley, 2001). Thus there is well known, that the inflammatory response has two components - cellular and exudative. The exudation is characterized by producing exudates i.e. fluids and cellular substances that are slowly discharged from blood vessels of inflamed tissues. The exudates contain proteins (fibrin and others) and could be released due to the increase of capillary permeability in the affected tissue. This process leads to the occurrence of oedema, thus by the measurement of swelling area the researcher can control the intensity of the inflammation. There is also important to remember that oedema distends the tissues, irritate the nervous receptors and can cause pain (Ley, 2001). The cellular component of the inflammation is presented by the emigration of leucocytes from the blood vessels into the inflamed tissues. Nevertheless for the research planned and conducted by the schedule of our training there is more important to recognise main mediators of the inflammation. There was demonstrated in the studies conducted recently (Ley, 2001; Sigal, 2005; Hildebrand, Pape & Krettek, 2005) that cytokines interleukin-1 and tumor necrotizing factors can play important role in the upregulation of the endothelial receptors and the processes of extravasation (i.e. e,igration of inflammatory cells into extravascular sites). This can increase intensity of swelling also. The vasoactive agents can influence on the processes of the exudation and extravasation significantly. Nevertheless they role are not studied completely. In the last decades the researchers pais great attention to the mechanisms of the impact of some vasoactive peptides on the microvascular responses during the acute and chronic inflammation. There are many candidates for profound studies in this area, nevertheless, some investigators prefer to use calcitonin gene-related peptide (CGRP) for modelling physiological reactions during the inflammatory response. This is a 37 amino acid peptide that is produced in the central and peripheral nervous system in the rodents (rats and mice). Since 1985 (Brain et al) there is known that CGRP is an extremely potent and long lasting microvascular vasodilator which can act to potentiate inflammatory oedema in skin induced by mediators of increased microvascular permeability (Chu et al., 2000, 2001). The substance P is is a key mediator of III type of hypersensitivity response (due to immune complexes). This kind of immune response is the pathogeneic backround for hundreds of chronic illnesses. There is known that local deposition of complexes in tissues or vessels can cause the inflammation with all its characteristic features: increased vascular permeability, exudation and leucocyte extravasation resulting in swelling (O'Conner et al., 2004). Nevertheless there is a lack of information about the pattern of simultaneous action of such pro-inflammatory mediators like substance P and classic vasodilatators, e.g. calcitonin gene-related peptide. This can be a subject of scientific research. One of the articles written by Mrs. Brain and coauthors (Buckley et al., 1991) was dedicated to the problem of time-dependent synergistic interactions between CGRP and other mediators of inflammation. The authors found that "oedema formation induced by a series of chemically distinct mediators of increased microvascular permeability; bradykinin, platelet activating factor (PAF), FMLP and zymosan-activated plasma; measured 0-30 min after i.d. injection was potentiated by CGRP" (p. 1515). These finding were confirmed in the researches conducted after this publication (Newbold & Brain, 1993). Nevertheless the possibility to repeat design and results of scientific research is the good indicator of its validity and evidence based approach (White & den Broek, 2004). The attempt to replicate data of the researches conducted by the group of British scientists from the Centre for Cardiovascular Biology & Medicine in New Hunt's House of King's College (London) could be interesting experience for any beginner in the immunopharmacological studies. There is necessary to state that the immunopharmacology as the research field of studies in the pharmacology is developed very actively in the modern days. There are several reasons for such activity. First of all the use of immunomodulators became wider and the effects of such medications should be studied properly before they will be implemented in the clinical medicine. Also, there is important to have effective indicators for the assessment of clinical effect of immunomodulating (i.e. immunosuppressive or immuno-stimulating) drugs. The measurement of inflammatory oedema could be very promising approach in the control of drugs action and in the researches of the inflammatory response. Because skin as the part of integument system of the alive organism can be examined both in vivo and in vitro and this object is very useful for laboratory experiments in the field of the immunopharmacology and physiology of the inflammatory response. The goal of this study is the evaluation of the effect of different vasocative substances on the intensity of imflamatory swelling. For accomplishing of stated goal there is necessary to implement the following objectives: To develop mice model for checking the hypothesis about the interaction of mediators of increased microvascular permeability and vasodilatators in the microciculation. To determine the intensity of the inflammatory swelling in the conditions when different vasoactive substances (e.g. substance P, CGRP, and their combinations) are used To determine the blood flow intensity during the inflammation when different vasoactive substances (e.g. substance P, CGRP, and their combinations) are used Methods and results. Mice (20-35 gram each) were used in the planned experiments. They were maintained on normal diet with free access to food and water in a climatically controlled environment. All experiments were carried out in accordance with animals scientific procedure (ACT 1986). The mice were anaesthetised by intraperitoneal injection of urethane in the dosage of 7 microgram per gram of weight. The dorsal skin was shaved, and the injection pattern has marked out. The oedema formation was measured by the extravascular accumulation of intravenously injected Evan blue in saline (2.5% w/v 0.1ml intravenously (into the tail vein) and then flushed through 0.1ml saline. After 5 minutes, substance P in the volume of 10 ml (300 pmol), CGRP in the volume of 10 ml (10 pmol), their combination (total volume is 10 ml) or Tyrode's solution (vehicle control) were injected intradermally, with one uninjected site to allow a comparison of injected site with intact skin. Oedema development was allowed for a 30 min period and the experiment was terminated. The dorsal skin was removed and the injection site was observed. The sites of the inflammatory swelling were measured. The skin oedema was expressed as its mean diameter of blueing (mm) and as its intensity (in the scores by 5-score scale). The animals were distributed into three groups (A, B and C) whereas each group include 4 mice. All group were comparable by the weight and age of animals. The statistical methods applied for analysing of data that were gained in the study included calculation of the mean, variance, standard deviation and standard error of mean. The statistical differences between the studied parameters were assessed by the use of paired Student's T-test while the difference were estimated as the significant if the value p2.0 P Read More