Treatment of experimentally induced partial-thickness burns in rats with different silver-impregnated dressings

Purpose: To evaluate the morphometric, macroscopic and microscopic aspects of experimentally induced partial-thickness burns in rats treated with different silver-based dressings. Methods: Wistar rats were used, divided into six treatments: saline (NaCl 0.9%); silver sulfadiazine 1%; Silvercel; Mepilex Ag; Aquacel Ag and Acticoat. The animals were monitored daily and euthanized at 7, 14 and 30 days after injury induction (DAI). Results: At 7 DAI, necrosis/crust was greater in control, silver sulfadiazine and Mepilex Ag treatments, granulation tissue was induced by Aquacel Ag, polymorphonuclear infiltrate (PMN) infiltration was intensified by Mepilex Ag; mononuclear infiltrate (MN) infiltration and angiogenesis were increased by Silvercel. At 14 DAI, hemorrhage was decreased by Silvercel and Mepilex Ag, PMN infiltration increased by Acticoat. At 30 DAI, angiogenesis was greater in the Acticoat treatment and fibroblasts were increased by Acticoat and Mepilex Ag. Collagen was induced at 14 DAI by silver sulfadiazine and Aquacel Ag and, at 30 DAI, by silver sulfadiazine and Silvercel treatments. Conclusions: Silvercel and Acticoat presented better results than the other products. However, all the dressings were better than the control at some point during the process, and may contribute to the healing of partial thickness burns. Silvercel and Aquacel Ag treatments induced better cosmetic outcomes regarding wound closure and scarring.

Cassava biopolymer polyamide hydrogel accelerates healing of induced skin woundsin rats / Hidrogel de biopolímero de poliamido de mandioca acelera o processo de cicatrização em feridas cutâneas induzidas em ratos

This study aimed to macroscopically and microscopically evaluate the healing of skin wounds induced in rats by topical application of cassava polyamide biopolymer hydrogel. In total, 32 rats were used and divided into four groups (n= 8): negative control - saline solution; positive control - use of commercial ointment; experimental group - I - ointment + cassava hydrogel; experimental group - II - cassava hydrogel. A 1cm2 wound induced on the animals dorsum was treated and evaluated. At day 21 post-operation, the animals were sacrificed by anesthetic overdose, and then 1cm2 of cicatricial skin from the wound region was collected. The material was cut to evaluate healing. In the macroscopic evaluation, complete healing was observed at the end of 21 days. Re-epithelialization was observed histologically; the connective tissue in the negative control, positive, and experimental - I groups was characterized by an abundance of collagen fibers, fibroblasts, and blood vessels. In experimental group - II additional healing was observed, as evidenced by the arrangement of collagen fibers and fibroblasts, and the reduction of neoformed vessels. Thus, we concluded that the hydrogel can assist in healing skin wounds, especially in the remodeling phase.(AU)

O objetivo deste estudo foi avaliar macro e microscopicamente a cicatrização de feridas cutâneas induzidas em ratos, a partir da aplicação tópica do hidrogel de biopolímero de poliamido de mandioca. Trinta e dois ratos foram divididos em quatro grupos (n= 8): controle negativo, tratado com solução salina; controle positivo, com pomada comercial; grupo experimental - I, com pomada + hidrogel de mandioca; grupo experimental - II, com hidrogel de mandioca. Feridas induzidas de 1cm 2 no dorso dos animais foram tratadas e avaliadas em intervalos de três a quatro dias. No 21º dia do pós-operatório, os animais foram mortos por aprofundamento anestésico, em seguida foi coletado 1cm 2 de pele da região cicatricial. O material foi cortado, corado pelas técnicas de hematoxilina-eosina e azocarmine-G, para avaliação da cicatrização. Na avaliação macroscópica, foi observada cicatrização completa no final do período de 21 dias. Histologicamente, observou-se reepitelização, o tecido conjuntivo no grupos controle negativo, positivo e experimental - I se caracterizou pela abundância de fibras colágenas, fibroblastos e vasos sanguíneos. No grupo experimental - II, a cicatrização sugere avanço de etapas, evidenciado pelo arranjo das fibras colágenas, pela redução de fibroblastos e dos vasos neoformados. Assim, foi possível concluir que o hidrogel de biopolímero de amido de mandioca pode auxiliar na cicatrização de feridas cutâneas, principalmente na fase de remodelação.(AU)

The Effect of a Hydrocolloid Dressing on Second Intention Wound Healing in Cats.

The objective of the present study was to evaluate the effect of a hydrocolloid dressing on second intention wound healing in cats. Two full-thickness skin wounds, measuring 2 × 2 cm, were created on both sides of the dorsal midline of 10 cats; bilaterally, one randomly selected wound was bandaged with a hydrocolloid dressing and the second one (control) with a semiocclusive pad. Subjective clinical evaluation of granulation tissue formation, of the quantity and nature of wound exudate, and planimetry were performed on the right-side wounds, and histological examination on the left. No significant differences in subjective clinical evaluation or in planimetry were observed between the hydrocolloid-treated wounds and controls. Most wounds had serous or absence of exudate (41.25% and 25%, respectively), whereas purulent exudate was observed in 7.5% of wounds. Edema was significantly increased in the hydrocolloid-treated wounds compared with controls on day 7 but no significant differences in the other histological variables were observed.

Preliminary evaluation of a hydrogel liquid bandage in 30 dogs undergoing tibial plateau levelling osteotomy surgery.

AIMS: To compare the prevalence of minor incisional complications in canine patients undergoing tibial plateau levelling osteotomy (TPLO) surgery that had a hydrogel liquid bandage (HLB) applied to their incision, with patients that had a light adhesive bandage applied. METHODS: Thirty dogs undergoing TPLO surgery were randomly assigned to either application of a light adhesive bandage to the incision, with removal 18-24 hours later, or application of a clear-drying polyethylene glycol HLB to the incision. Erythema, swelling, discharge, and dehiscence were assessed 1 day (Day 1) and 10-14 days (Days 10-14) postoperatively. All persons completing the assessment were blinded to the treatment. Outcomes were compared for the two groups using Fisher's Exact Test. RESULTS: On both Day 1 and Days 10-14, the distribution of dogs with erthemyma or swelling did not differ between the two groups (p≥0.4). The prevalence of erythema was the same in the bandage and HLB groups at Day 1 (11/15; 73%) and was similar at Days 10-14 (3/11 (27%) and 2/11 (18%), respectively). Prevalence of swelling was also the same in the two groups on Day 1 (11/15; 73%) and was similar at Days 10-14 (3/11 (27%) and 6/11 (55%), respectively). On Day 1, 2/15 (13%) dogs in the HLB group and none of the dogs in the bandage group had incisional discharge (p=0.483). No dogs were observed with discharge on Days 10-14. No dehiscence, infection, or any other major incisional complication was observed in either group at any point in the study. CONCLUSIONS: Preliminary results suggest that prevalence of minor incisional complications after TPLO surgery treated with HLB or with a traditional adhesive bandage may be comparable. No major adverse effects were seen with the use of HLB. CLINICIAL RELEVANCE: Due to several disadvantages of traditional bandaging, which can require post-operative maintenance and removal, lasts only a short time, and be painful when removed, an alternative with fewer drawbacks is desirable. HLB may present such an alternative.

Effects of two occlusive, hydrocolloid dressings on healing of full-thickness skin wounds in cats.

OBJECTIVES: To determine the effects of two occlusive, hydrocolloid dressings on second intention wound healing in cats. METHODS: Three 2×2 cm full-thickness skin wounds were created on each side of the trunk of 10 cats. Two bilateral wounds were bandaged using different hydrocolloid dressings, namely Hydrocoll and DuoDerm while a semi-occlusive pad (Melolin) was applied to the third bilateral wound (control group). Wound planimetry, subjective evaluation of wound healing, and qualitative bacterial cultures were performed on the right-sided wounds, whereas left-sided wounds were subjected to histological examination. RESULTS: Subjective evaluation revealed accelerated (p <0.01) granulation tissue formation in hydrocolloid-treated wounds. The amount of wound exudate was initially greater (p <0.01) in these wounds. Seventeen out of 120 evaluated wounds (14.2%) produced purulent exudate, 11 of which showed Staphylococcus aureus growth. Fewer control wounds (3/17) emitted purulent exudate, but all of them yielded moderate bacterial growth as compared to hydrocolloid-treated wounds (8/17) which had a low incidence of bacterial growth. The only significant difference in histological variables was increased cellular infiltration noted on day 7 in Hydrocoll-treated wounds compared to controls. No significant differences in planimetry variables were found between groups. CLINICAL SIGNIFICANCE: Despite the initially increased amount of wound exudate and the low growth of Staphylococcus aureus, hydrocolloid dressings accelerate granulation tissue formation and can hence be suggested for second intention wound healing in cats.

Effect of a hydrocolloid dressing on first intention healing surgical wounds in the dog: a pilot study.

OBJECTIVES: To evaluate the efficacy of a hydrocolloid dressing for the treatment of surgical wounds in dogs. METHODS: Six healthy young female dogs of medium size and different breed underwent ovariohysterectomy. Histological evaluation was performed on biopsies taken from the edges of the wounds at day 7. The dressing was applied on one half of the wound according to manufacturer's instructions; the second half served as control. Biopsy specimens were fixed in a 10% formalin buffered solution pH 7.4, paraffin embedded and stained with haematoxylin and eosin. For clinical assessment, the presence and quality of exudate, erythema of the surrounding area, swelling and correct apposition of the wound margins were evaluated. RESULTS: The hydrocolloid dressing was easy to use. The clinical quality of the treated skin wounds was superior to the non-treated ones. Comparison of histological features between treated and untreated wounds showed a more regular organisation of the granulation tissue in the treated wounds, with fibroblasts being aligned parallel to the overlying epidermis. The number of inflammatory cells and the extension of granulation tissue were less prominent and less widespread in treated compared to untreated wounds. CONCLUSION: The dressing performed very well in terms of adhesiveness and flexibility. It was useful in the management of surgical wounds to avoid contamination and ameliorate the epithelialisation rate and granulation tissue morphology of the surgical scar.

In vitro study of the effectiveness of different dressings for debriding fibrin in blood clots from horses.

Franz diffusion cells containing uniformly dehydrated equine blood clots to simulate fibrinous eschar were used to measure the rate of debridement of fibrin by novel and traditional wound dressings, under standardised conditions of temperature, pH and humidity. Significant increases in protein breakdown occurred within 24 hours with all the dressings, but not thereafter. In general, dressings hydrated in normal saline were better as debriding agents than dressings hydrated in water. Autolytic debriding agents were 47 per cent more effective than chemical debriding agents; specifically, hydrofibre and gauze dressings hydrated in saline broke down more than 3500 microg/ml of protein whereas dressings impregnated with proteolytic enzymatic agents digested less than 1400 microg/ml.