Complex treatment of wounds using serotonin, antioxidants, and exogenous nitric oxide

The dissertation is devoted to an experimental study of the combined effect of serotonin, the antioxidant Mexidol, and exogenous nitric oxide (NO therapy) on the course of the wound process in models of a sutured linear and a full-thickness planar skin wound. The research aims to find means of preventing purulent complications and stimulating the healing of postoperative wounds. The study employs clinical observations, tensiometry, planimetry, histological, histochemical, and morphometric methods, as well as statistical analysis of the data obtained. The influence of Anicol ointment on the healing of linear wounds is additionally assessed.

The author establishes that serotonin adipate, Mexidol, and NO-containing gas flows, including in combined use, reduce inflammatory manifestations, accelerate reparative processes, and promote the formation of a thin scar. The best results are obtained with the combination of NO therapy and serotonin administration, which is regarded as a promising direction for further research.

Relevance of the topic

The prevention of purulent complications and the stimulation of postoperative wound healing in surgery remain topical, because purulent infection is the most serious complication both in terms of mortality and material expenditure (V.I.Struchkov, 1985; V.K.Gostishchev, 1997). According to V.I.Struchkov (1983), in the USSR postoperative purulent complications developed on average in 10% of cases. The situation is no better at present: the number of postoperative purulent complications ranges from 2 to 17% (B.S.Briskin et al., 2002).

The cause of frequent purulent complications and secondary-intention healing of postoperative wounds, as well as the chronicity of planar wounds, in addition to primary tissue contamination, lies in both external (surgical) and internal factors. External factors include the suture material used, breaches of asepsis, hospital infection, virulence of the microflora, excessive tissue traumatization, prolonged and aggressive operative intervention, and others. Internal factors include the immunological reactivity of the organism, increased allergization of the population, general and local disturbances of blood flow, the presence of devitalized tissues, and concomitant diseases (diabetes mellitus, malignant neoplasms, anaemia, obesity, alimentary and vitamin deficiency, etc.). To these one may also add disturbances of the haemostasis system, phagocytosis, free-radical reactions, intercellular interactions in wound tissues (in particular the production of cytokines, proteases, and collagenases), and other factors (V.I.Struchkov et al., 1984; P.I.Tolstykh et al., 2000; A.B.Shekhter, 1995; M.P.Tolstykh et al., 2004). Undoubtedly, the virulence of the microorganisms themselves and their resistance to antibacterial drugs play an important role.

To address this most important surgical problem, numerous medicinal agents, biologically active substances, and dressing materials, as well as various physico-chemical factors (laser radiation, hyperbaric oxygenation, ozone therapy, photodynamic therapy, Mexidol, serotonin, Anicol ointment, etc.) have been proposed. However, the development and testing of new agents and methods of treatment, as well as new therapeutic technologies that combine an antibacterial effect, an influence on microcirculation, the stimulation of cytokine production and fibroblast proliferation, and, ultimately, accelerate wound healing, remain highly topical.

Mexidol is used for the treatment of wounds and the prevention of purulent complications (L.P.Lapshikhin, 2001; M.P.Tolstykh et al., 2005) due to its antioxidant activity, which relieves oxidative stress in damaged tissues and diminishes inflammatory manifestations, including microcirculatory disturbances, as well as owing to its membrane-protective action.

Serotonin, as a biogenic amine, participates in a number of important physiological functions: the transmission of nerve impulses, the regulation of gastrointestinal motility, haemostasis, and vascular reactions, while under different conditions it exhibits both vasoconstrictor and vasodilator effects, which in itself can influence the wound process. In recent years serotonin has come to be regarded as a modulator of regeneration, since it acts not only on vascular tone but also on the proliferation of fibroblasts and smooth muscle cells and induces a number of other anabolic reactions (W.L.Lowe et al., 1993). Publications have appeared showing that serotonin accelerates the healing of chronic wounds in animals (M.Engelen et al., 2004), experimental gastric ulcers (M.O.Klimenko et al., 2000), and purulent neuro-trophic ulcers of the lower limbs in diabetic patients (S.A.Orudzheva et al., 2005). However, data on the effect of serotonin on wounds are highly contradictory; there are no studies on the influence of serotonin on non-infected linear and planar wounds and on the possibility of preventing their purulent complications, nor are there studies on the combined action of serotonin with other drugs, including Mexidol.

In recent years a new direction in Russian medicine has been developing — NO therapy, based on the use of exogenous nitric oxide (NO) generated from atmospheric air by the Plazon plasma-tron apparatus. Endogenous NO, discovered only at the end of the twentieth century, is a universal regulator of diverse physiological processes and participates in various pathological and regenerative processes, including inflammation and wound healing. NO therapy of the wound process, according to A.B.Shekhter et al. (1998, 2001); S.V.Grachev (2001); and A.B.Shekhter et al. (2005), is a powerful stimulator of the wound process, especially in complicated wounds (purulent, gunshot, trophic, and diabetic ulcers, long-term non-healing wounds in oncology, etc.).

At the same time, there are almost no studies devoted to the prevention of purulent complications and to the stimulation of postoperative wound healing. There are likewise no studies on the combination of NO therapy with Mexidol and serotonin, although the pathogenetic significance of such a combination is justified, since according to the literature (F.M.Faraci, D.D.Heistad, 1992) NO is an inhibitor of the vasoconstrictor action of serotonin, thereby enhancing its vasodilator effect and the normalization of microcirculation.

Anicol ointment, developed at the Perm Pharmaceutical Academy, contains the local anaesthetic anilocaine 5% and dimexide 20%. Its developers recommend it for use in the second phase of the wound process in purulent surgical diseases, trophic ulcers, osteomyelitis, etc. In 1997 the Pharmacological Committee recommended Anicol ointment for clinical trials. However, the literature available to us contains no information on the results of experimental and clinical studies of the therapeutic efficacy of Anicol ointment in the treatment of wounds.

Aim of the study

To investigate the possibility and to determine the feasibility of using a number of new medicinal and biologically active agents and their combinations for the prevention of purulent complications and the treatment of wounds in an experiment on models of a sutured linear and a full-thickness planar skin wound.

To achieve this aim the following tasks were set:

1. To carry out, in an experiment, a comparative study of the healing and quality of scarring of linear wounds under the action of Mexidol, serotonin adipate, Anicol ointment, and NO-containing gas flows (NO-CGF), as well as under their combined action.

2. To perform a comparative histological and histochemical study of the wound process in linear wounds and the features of their scarring under the action of all the above-mentioned agents and their combinations, using quantitative morphometric and semi-quantitative scoring assessments. To carry out a comparative statistical analysis of the data obtained.

3. On the basis of the data obtained, to select the optimal methods for the prevention of purulent complications and the stimulation of wound healing.

4. To give a comparative assessment of the dynamics of healing of full-thickness planar skin wounds under the influence of NO therapy and its combination with intraperitoneal administration of serotonin.

5. To give a morphological assessment of the wound process in full-thickness planar wounds under the influence of NO therapy and its combination with intraperitoneal administration of serotonin.

Scientific novelty

• For the first time, using tensiometric, morphological, and morphometric studies in an experiment, it has been proved that serotonin adipate, administered intraperitoneally per se or in combination with the antioxidant Mexidol, ensures the prevention of purulent complications, reduces inflammatory and enhances reparative manifestations, and accelerates the formation of the scar and the epithelialization of linear wounds.

It has been established for the first time that NO therapy of a linear wound, including in combination with Mexidol and, especially, with serotonin, completely prevents the development of purulent complications in experimental linear wounds, weakens or eliminates inflammatory changes, sharply accelerates the reparative and scarring phases of the wound process, and promotes the formation of a very thin, straight, «cosmetic» scar. The best results have been obtained with the combination of NO therapy and serotonin.

It has been established for the first time by planimetric and morphological methods that the wound process in an experimental full-thickness planar wound under the influence of NO therapy and, especially, in combination with intraperitoneal administration of serotonin is markedly accelerated compared with the control (without treatment). Phagocytosis is activated and wound cleansing is accelerated, the macrophage reaction, fibroblast proliferation, and neoangiogenesis are intensified, and the transition of the inflammatory phase of the wound process to the proliferative-reparative phase and then to the scarring and epithelialization phase is accelerated.

Experimental studies indicate the promise of NO therapy, including in combination with serotonin, for the prevention of purulent complications and the acceleration of healing of aseptic sutured linear and full-thickness planar wounds. Under experimental conditions, on the model of a sutured linear wound, it has been reliably established that Anicol ointment, while stimulating epithelialization, exerts no anti-inflammatory effect and does not ensure the prevention of purulent complications in linear wounds.

Practical significance

The data obtained constitute an experimental-theoretical substantiation of the practical application of new therapeutic technologies: the combination of NO therapy with serotonin adipate, the use of serotonin adipate per se or in combination with the antioxidant Mexidol; they open the prospect of their further study as means of preventing and treating purulent complications of postoperative wounds. On the basis of the patterns revealed, regimens and schemes for the application of the studied new medicinal and biologically active agents and their combinations, ensuring the desired therapeutic effect, may be selected. The features revealed of the influence of Anicol ointment on the healing of linear wounds make it possible to recommend it for use only in the second phase of the wound process to speed epithelialization, but not for the prevention of purulent complications.

Approval of the work

The work was approved at the scientific conference of the Department of Faculty Surgery No. 1 of MGMSU «Roszdrav» on 10 February 2006.

The main propositions of the dissertation were reported at:

• The XII Scientific-Practical Conference «Mytishchi City Clinical Hospital: «Clinical Readings», dedicated to the 60th anniversary of victory in the Great Patriotic War of 1941–1945», (Mytishchi, 2005);

• The XXVIII Final Scientific Conference of Young Scientists of SEI HPE MGMSU (Moscow, 2006);

Publications

Four printed works have been published on the topic of the dissertation.

Scope and structure of the dissertation

The dissertation is set out on 153 pages of typewritten text and consists of an introduction, 3 chapters, a conclusion, findings, practical recommendations, and a bibliography containing 174 sources, of which 90 are in Russian and