Content area
Full Text
ABSTRACT
The aim of the present study was to evaluate the effect of hyperbaric oxygen therapy (HBO^sub 2^) on the healing process of ischemic colonic anastomoses in rats. Forty Wistar rats were divided into four groups: control (Group I), control and HBO^sub 2^ (Group II), ischemia (Group III), ischemia and HBO^sub 2^ (Group IV). Ischemia was achieved by clamping four centimeters of the colonic arcade. On the eighth therapy day, the anastomotic region was removed for quantification of hydroxyproline and immunohistochemical determination of metalloproteinases 1 and 9 (MMP1, MMP9). The immunohistochemical studies showed significantly larger metalloproteinaselabeled areas in Group IV compared with Group III for both MMP1 and MMP9 (p<0.01). This finding points to a higher remodeling activity of the anastomoses in this experimental group. Additionally, animals subjected to hyperbaric oxygen therapy showed both a reduction in interstitial edema and an increase in hydroxyproline concentrations [at the anastomotic site]. Therefore, we conclude that HBO^sub 2^ is indeed beneficial in anastomotic ischemia.
INTRODUCTION
The incidence of colonic anastomotic dehiscence is influenced by various factors, including the mechanical preparation of the colon, the surgical technique applied [1-4], the use of certain pharmacological agents, the patient's general condition [5], as well as the vascularization and oxygen tension in the tissue around the anastomosis [6,7].
The synthesis and development of collagen fibers and, consequently, the appropriate tension of the intestinal wall are directly associated with the partial oxygen pressure [8]. Thus, administration of oxygen is crucial under conditions that potentially impair healing processes. In addition to the concomitant loss of tensile force, ischemic anastomoses are characterized by diminished levels of hydroxyproline and rise in the amount of free radicals [9]. Clinical studies have demonstrated that hyperbaric oxygen therapy (HBO^sub 2^) increases proliferation of fibroblasts [10] and enhances the angiogenetic potential of ischemic tissues. Hence, HBO^sub 2^ promotes healing processes by optimizing the mechanism through which polymorphonuclear leukocytes combat infections [11,12]. Therefore, HBO^sub 2^ can aid healing processes after an anastomosis has suffered ischemia, as in the case of patients with postoperative hemodynamic instability due to technical difficulties during the surgery, which in turn culminated in anastomotic ischemia. Using rats, Hamzagoul et al. [13] have demonstrated that application of HBO^sub 2^ augmented the partial oxygen pressure (ppO^sub 2^)...