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Background: Intracavitary irrigation is a routine component of many surgical procedures, especially in those involving a contaminated field. Normal saline remains the irrigant of choice for most surgeons. Hypochlorous acid is a weak acid that produces hypochlorite ions with antimicrobial properties. Reducing microbial concentration during intracavitary irrigation is a potential benefit of using hypochlorous acid solution over normal saline. In this study, the safety of hypochlorous acid solution for intracavitary lavage was compared with normal saline in a rat model of 3 surgical procedures—laminectomy, thoracotomy, and laparotomy. Methods: The intracavitary space was lavaged with either normal saline or hypochlorous acid. The procedures were also completed using Dakin's solution (sodium hypochlorite) as a comparator, given its known cytotoxicity. On postoperative day 5, necropsies of all animals were performed and relevant organs and blood samples obtained. Histology (hematoxylin and eosin staining) was used to examine biopsies of the collected organs for signs of inflammation, blood vessel integrity, and necrosis. Immunohistochemistry staining for caspase-3 was used to identify apoptotic cells. Results: There were no differences in outcomes (survival, pain, and time to recovery) or histology between animals lavaged with hypochlorous acid and normal saline. Intact organ-specific architecture was observed in both groups. In comparison, rats treated with Dakin's solution demonstrated significant capsular fibrosis and hemorrhage. Furthermore, significant apoptosis was noted within the bowel mesentery of the group treated with Dakin's solution when stained for caspase-3. Conclusion: Hypochlorous acid is safe for lavage of intraperitoneal, intrathecal, and intrathoracic cavities. Further studies should be conducted to demonstrate efficacy of hypochlorous acid in an infected field.

Objective: Proteins of the matrix metalloproteinases family play a vital role in extracellular matrix maintenance and basic physiological processes in tissue homeostasis. The function and activities of matrix metalloproteinases in response to compression therapies have yet to be defined. Here, a swine model of hypertrophic scar was used to profile the transcription of all known 26 matrix metalloproteinases in scars treated with a precise compression dose. Methods: Full-thickness excisional wounds were created. Wounds underwent healing and scar formation. A subset of scars underwent 2 weeks of compression therapy. Biopsy specimens were preserved, and microarrays, reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry were performed to characterize the transcription and expression of various matrix metalloproteinase family members. Results: Microarray results showed that 13 of the known 26 matrix metalloproteinases were differentially transcribed in wounds relative to the preinjury skin. The predominant upregulation of these matrix metalloproteinases during early wound-healing stages declined gradually in later stages of wound healing. The use of compression therapy reduced this decline in 10 of the 13 differentially regulated matrix metalloproteinases. Further investigation of MMP7 using reverse transcription-polymerase chain reaction confirmed the effect of compression on transcript levels. Assessment of MMP7 at the protein level using Western blotting and immunohistochemistry was concordant. Conclusions: In a swine model of hypertrophic scar, the application of compression to hypertrophic scar attenuated a trend of decreasing levels of matrix metalloproteinases during the process of hypertrophic wound healing, including MMP7, whose enzyme regulation was confirmed at the protein level.

Objective: Burn-injured patients are highly susceptible to infectious complications, which are often associated with increased morbidity and mortality. Rates of antibiotic resistance have increased, and resistant species such as methicillin-resistant Staphylococcus aureus provide additional challenges in the form of virulence factors. Proteins can disrupt local healing, leading to systemic immune disruption. To optimize outcomes, treatments that reduce pathogenicity must be identified. This study aims to compare a glycylcycline antibiotic—tigecycline—with clindamycin for effectiveness in treating superantigenic methicillin-resistant Staphylococcus aureus in burn wounds. Methods: Sprague-Dawley rats received paired 2 × 2-cm burn wounds, which were subsequently inoculated with known virulence factor–producing methicillin-resistant Staphylococcus aureus or media alone on postinjury day 1. Infected animals received twice-daily tigecycline (high or low dose), twice-daily clindamycin (high or low dose), or saline alone (positive controls). Daily sampling and imaging assessments were performed. Results: Bacterial counts and toxin levels were reduced significantly in antibiotic-treated groups relative to positive controls (P < .001). Results from day 7 showed measurable toxin levels in clindamycin-treated, but not tigecycline-treated, wounds. Imaging analysis revealed a return of wound perfusion in tigecycline-treated animals similar to the sham animals. Transcript analysis using polymerase chain reaction and polymerase chain reaction arrays demonstrated downregulation of gene expression in antibiotic-treated animals as compared with positive controls. Conclusions: Overall, this study supports the use of tigecycline in the treatment of methicillin-resistant Staphylococcus aureus–infected burn wounds. While both protein synthesis inhibitors are effective, tigecycline appears to be superior in controlling toxin levels, enabling better wound healing.