@2024 Afarand., IRAN

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ISSN: 2252-0805    The Horizon of Medical Sciences 2018;24(2):119-124

Background
Burns are considered as one of the major injuries worldwide, usually leading to serious medical attention and hospitalization in burned subjects [1].
Previous Studies
... [2-7]. Douglas in 1952, developed using the human placenta layers for the first time as a temporary biological method of wound dressing followed by Sabela (1913), who used human placenta layers for healing burn wounds. The results of their studies showed that amniotic membrane inhibits the migration of polymorphonuclear leukocytes (PMN) and stimulates the tissue coverage and acceleration in the formation of granular tissue in the wound region and subsequently resulting in a faster wound healing [8]. Silver Sulfadiazine cream 1% is commonly used worldwide as a common method of dressing for partial-thickness burns or even selectively for major burns. It is more used as an antimicrobial agent compared with other compounds, like silver nitrate, sulfamilone and acetaminophen. Unfortunately, despite its beneficial effects, topical administration causes some systemic side effects, such as neutropenia, erythema, crystalluria and methemoglobinemia. Some recent studies have also shown that its use in partial-thickness burns may delay burn healing [9-12]
Aim(s)
Our objective was to evaluate the healing of second-degree burns in male rats treated with topical application of placental amniotic membrane alone or impregnated with topical Silver sulfadiazine cream in male rats.
Research type
This study is an experimental study.
Research society, place and time
This study was conducted on 64 male Wistar rats in the Qazvin University of Medical Sciences in 2015.
Sampling method and number
Mice were randomly divided into 4 groups (N=16). The number of samples was determined based on similar studies.
Used devices&materials
Rats were kept in standard laboratory conditions (room temperature 21±2°C) with 12 h dark/light cycle and free access to food. The study was first approved by the Ethics Committee of the Qazvin University of Medical Sciences and all protocols used in this study were in accordance with the Ethical Guidelines of the Helsinki Declaration (1975). Prior burning, the hair surrounding the neck of the rats was shaved using a standard shaving machine. Animals were anesthetized by intraperitoneally injection of ketamine (40 mg/kg) (GmbH, Germany) and Xylasein (5 mg/kg) (Galway, Ireland) and a circular hot iron stomp was used for burning (about 80°C; 1.75 cm diameter) for 1 second. Second-degree burn burns was confirmed by the pathology slide and H & E eosin staining [13]. The groups included: 1. Control (simple dressing with normal saline), 2. Dressing with topical application of placental amniotic membrane, 3. Dressing with silver sulfadiazine cream (1%; Sobhan Co.). 4. Dressing with silver sulfadiazine cream plus placental amniotic membrane. The wound was cleaned and necrotic tissue was removed daily and a new dressing was employed with normal saline or the topical application of silver sulfadiazine (1 mm) or application of placental amniotic membrane impregnated with 1% silver sulfadiazine. In order to prevent the risk of infection, a medical history of women with normal pregnancy was reviewed and laboratory studies were carried out, and the subjects suspected with cancer, infectious diseases, narcotics, hepatitis B and C and HIV were excluded. Following elective cesarean section (Kosar Hospital, Qazvin), the embryonic segments were removed under the hood and then washed with Ringer's solution under sterile conditions. The amniotic layer was removed and transferred to the cold sterilized containers (4°C) and evaluated immediately. In order to remove blood and other contaminants, it was washed four times with normal saline and once with Dakins solution (Sodium Hypochlorite solution 0.25%) and then re-washed with normal saline. Each specimen was then divided into the considered parts to be transferred to the sterile containers and stored in a refrigerator (4°C). These procedures were done in less than 2 h. At the end of day 7, 14, 21 and 28 under general anesthesia, shear wave elestography (SWE) of the burn site and its surrounding was performed for microscopic evaluation. SWE was done in the same site on different days [14]. The tissue samples were fixed at 10% with brafemarin followed by passage, processing, embedding in paraffin, and cutting at a microtome setting of 5 microns. After H & E staining, the slides were evaluated with an optical microscope for the number of PMN leukocytes, fibroblasts and new blood vessels. Olympus DP25 camera was used to capture images from all samples and a blind survey was done using Cellsens software by researcher [15]. The wound surface was evaluated on days 7, 14, 21 and 28 and the following formula was used to assess the healing: Wound surface (%) = (Wound surface on the considered day * 100) × Wound surface on the first day Healing (%) = (100-wound surface (%)) The control and evaluating of the healing was done by one researcher blind to the treatments. Data was analyzed using SPSS 19 software and data analysis was done by one way ANOVA and Tukey's post hoc tests.
Findings by Text
On the 7th day, the wound tissue contained large amounts of nicotroic mucosa mixed with inflammatory cells (mainly with PMN leukocytes) as well as degeneration of the epidermis. In addition, angiogenesis was just begun, and the early stages of the replacement of granular tissue was initiated at the beneath of dermis. Additionally, edema and inflammatory degeneration of the loose connective tissue could be seen. At this stage, PMN leukocyte count in treated animals was significantly lower than the control group (p<0.001), but there was no significant difference between the three treatment groups (Table 1). Histology of the wound 14 days after burning showed that the thickness of burn wound was decreased in all groups, however exudate fibrino-leukocytic secretions were still observed. Several chronic inflammatory cells (lymphocytes, plasma cells and macrophages) were replaced by acute inflammatory cells, and new granulomas and blood vessels were observed. At this stage and through following weeks, the number of new fibroblasts and vascular channels (except for the fourth week) was significantly higher in the treated groups than the control group (p<0.001); however, there was no significant difference between the three treatment groups (Tables 2 and 3). The percentage of wound healing on days 7, 14, 21, and 28 in the groups treated with sulfasalazine, placental amniotic membrane plus sulfasalazine and placental amniotic membrane was significantly greater than the control group (p<0.001; Table 4). Moreover, in the 21st and 28th weeks, the following factors in the placental amniotic membrane treated group were more than the control group: granulation tissue organization, fibroblast density and collagen fiber sedimentation. In addition, at the end of the 4th week, epithelialization of the central site of wound in the control group seemed still incomplete (Table 4).
Main comparison to the similar studies
In a relatively similar study, the effectiveness of dressing with placental amniotic membrane for graft donor sites in comparison with conventional antibiotic dressings (silver sulfadiazine cream) was evaluated in 42 patients with second and third-degree burns. There was no significant difference in infection rate in two methods. However, patients were more cooperated in replacing the dressing with amniotic fluid. Also, wound healing in the dressing with amniotic membrane was four days reduced [16]. In another study, Mohammadi et al. examined the effects of dressing with silver sulfadiazine and placental amniotic membrane in burn wounds. and showed that in patients with placental amniotic membrane dressing, albumin injection, analgesics, and infection were higher than the sulforadiazine group [17].
Suggestions
Further studies especially for third-degree burns are recommended.
Limitations
The limited financial resources restricted the development of methods and the number of samples.
Conclusions
Due to the similar effects of the dressing with placental amniotic membrane and sulfadiazine cream in wound healing, it is recommended that they be used as an appropriate candidate for treatment of burn wounds.
Acknowledgments
The authors are sincerely thankful to all who helped us in this project.
Conflict of interest
None declared.
Ethical Permissions
None declared.
Funding Sources
This research was funded by the Vice-Chancellor of Qazvin University of Medical Sciences.

TABLES and CHARTS

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