Rat Skin Tissue Research Articles

Protective effect of Isoliquiritigenin on skin ischemia-reperfusion injury in rats

Abstract Skin ischemia-reperfusion (I/R) injury is a serious condition that compromises skin flap surgery and leads to organ dysfunction. It arose due to restoration of blood supply after prolonged ischemia. The present study was conducted to explore the possible protective Isoliquiritigenin (ISL) on skin ischemia-reperfusion injury in rats. The ISL was administered to rats in the dose of 10 mg/kg, 20 mg/kg, and 30 mg/kg. The effect of ISL was quantified on the skin tissue of rats following the I/R injury on various indices of inflammation, oxidative stress, and apoptosis together with the effect on skin survival. ISL improves the survival of skin which is further confirmed by the histopathological analysis. It also causes a reduction of apoptosis as shown by TUNEL staining. The level of oxidative stress was found significantly reduced by restoring the MDA, SOD, and GSH levels near to normal. The level of inflammation was also decreased as suggested by reduced level of cytokines, such as TNF-α, IL-1β, and IL-6. The ISL also causes a significant reduction of COX-2 and iNOS in western blot analysis. Collectively, our study has shown a beneficial effect of ISL against skin I/R injury via multiple mechanisms of action, such as attenuation of oxidative stress, inflammation, and apoptosis.

Towards Accurate Microwave Characterization of Tissues: Sensing Depth Analysis of Open-Ended Coaxial Probes with Ex Vivo Rat Breast and Skin Tissues.

Dielectric properties of biological materials are commonly characterized with open-ended coaxial probes due to the broadband and non-destructive measurement capabilities. Recently, potential diagnostics applications of the technique have been investigated. Although the technique can successfully classify the tissues with different dielectric properties, the classification accuracy can be improved for tissues with similar dielectric properties. Increase in classification accuracy can be achieved by addressing the error sources. One well-known error source contributing to low measurement accuracy is tissue heterogeneity. To mitigate this error source, there is a need define the probe sensing depth. Such knowledge can enable application-specific probe selection or design. The sensing depth can also be used as an input to the classification algorithms which can potentially improve the tissue classification accuracy. Towards this goal, this work investigates the sensing depth of a commercially available 2.2 mm aperture diameter probe with double-layered configurations using ex vivo rat breast and skin tissues. It was concluded that the dielectric property contrast between the heterogeneous tissue components has an effect on the sensing depth. Also, a membrane layer (between 0.4–0.8 mm thickness) on the rat wet skin tissue and breast tissue will potentially affect the dielectric property measurement results by 52% to 84%.

BFGF and collagen matrix hydrogel attenuates burn wound inflammation through activation of ERK and TRK pathway

Burn injuries are most challenging to manage since it causes loss of the integrity of large portions of the skin leading to major disability or even death. Over the years, hydrogels are considered as a significant delivery system for wound treatment because of several advantages over other conventional formulations. We hypothesized that the bFGF-collagen-AgSD incorporated hydrogel formulation can accelerate the rate of burn healing in animal model and would promote fibroblast cell proliferation. Neovascularization and re-epithelialization is a hall mark of burn wound healing. In the present study, histopathological investigation and scanning electron microscopy of skin tissue of Wistar rats showed almost complete epithelialisation after 16 days in the treatment group. The developed hydrogel showed significantly accelerated wound closure compared with a standard and control group. The faster wound closure resulted from increased re-epithelialization and granulation tissue formation because of the presence of collagen and growth factor. Expressions of proteins such as TrkA, p- TrkA, ERK1/2, p-ERK1/2, NF-kβ, and p-NF-kβ involved in nerve growth factor (NGF) signalling pathway were analysed by western blot. All the findings obtained from this study indicated that the hydrogel can be considered as a promising delivery system against second degree burn by faster healing.

Employing optical microscopy technique to determine the tissue action of Hamamelis virginianaL. (Hamamelidaceae), Maytenus ilicifoliaMart. ex Reissek (Celastraceae) and Casearia sylvestris Sw. (Salicaceae) tinctures on skin-fixed histological sections of Wistar rats

Objective: In this study, we aimed to determine the action of the tinctures of Hamamelis virginiana, Maytenus ilicifolia, and Casearia sylvestris on tissues. For this, we investigated the histological sections of fixed skin tissue of Wistar rats for the changes in collagen and elastic fibers, epithelial cells, conjunctive cells, epidermal attachments, pigments, and granules using the optical microscopy technique. Since in the literature and published articles, the use of in vivo models, such as Wistar rats, is predominant to evaluate the healing action of herbal medicines. Methods: The tinctures of Hamamelis virginiana, Maytenus ilicifolia, and Casearia sylvestris, and ethanol 70% (blank) were used. The tinctures were obtained at 10% (w/v) through percolation using 70% ethanol (v/v) as the extraction liquid. This study was conducted in duplicate for each tincture and different incubation times (4, 24, and 48 h) at 37 °C in an oven. The slides used in this study (Wistar rat skin) were previously processed at the histology laboratory since the waste material was donated to conduct this experiment. The Research Ethics Committee approved the use of animals of the Life Sciences Center of the Pontifical Catholic University of Campinas (PUC-CAMPINAS) under the protocol approval number 367/08. Before initiating the staining process, the slides were removed from the oven, and the tincture deposited on the slides was removed. Weigert staining was performed subsequently. For semi-quantitative analysis, the histological sections were carefully observed, and the number of collagen and elastic fibers was evaluated based on the following scale: (+) normal fiber presence, (−) slight decrease, (− −) moderate decrease, and (− − −) intense decrease. The images were digitally captured to obtain the results using a photomicroscope. Results: The degradation of collagen fibers was best evidenced upon using Hamamelis virginiana tincture, which is concordant with the existing reports in the literature on its healing action via the precipitation of dermal proteins. Maytenus ilicifolia and Casearia sylvestris tinctures exhibited low proteolytic capacity as they only caused degradation of elastic fibers that are more delicate and very different from collagen in their constitution. Therefore, the application of the latter two as healing agents (which acts through precipitating proteins) is limited. Conclusions: This experimental histological model using the optical microscopy technique exhibits the advantage of agility and high efficiency as a simple and powerful approach.

Downregulation of miR‑27b promotes skin wound healing in a rat model of scald burn by promoting fibroblast proliferation

The aim of the present study was to investigate the effect and mechanism of action of microRNA (miR)-27b on skin wound healing in rats with deep second-degree scald burns and in BJ human skin fibroblast cells. Rat models with deep second-degree scald burns were constructed and injected with miR-27b mimics and inhibitors at the wound site daily for 21 days. Healing of burned skin tissues was observed at 0, 3, 7, 14 and 21 days following modeling. H&E and Masson staining were used to observe the pathological structure and degree of collagen fibers in the burned skin tissues. The effects of miR-27b on BJ cell proliferation and migration were determined by MTT and scratch assays. Matrix metalloproteinase-1 (MMP-1), α-smooth muscle actin (α-SMA), collagen I and collagen III expression in rat skin tissues and BJ cells were measured via reverse transcription-quantitative PCR and western blot analysis. The results of the in vivo experiments demonstrated that miR-27b inhibition accelerated scalded skin healing and induced fibroblast growth. Furthermore, the in vitro experiments revealed that miR-27b inhibition increased BJ cell proliferation and migration. Furthermore, miR-27b inhibition upregulated MMP-1, α-SMA, collagen I and collagen III expression in the skin tissues and cells, while the overexpression of miR-27b demonstrated the opposite effect. In conclusion, the results of the present study revealed that miR-27b inhibition increased fibroblast proliferation, thereby accelerating scald wound healing in rats.

Transdermal Delivery of Small-Sized Resveratrol Nanoparticles to Epidermis Using Anionic Phospholipids

Composite nanoparticles composed of anionic phospholipid of 1,2-dipalmitoyl- sn-glycero-3-phosphorylglycerol (DPPG) and resveratrol (Res) were successfully prepared by mixing them in water and a subsequent heating/cooling process. Small-sized DPPG-Res nanoparticles (<60 nm) could be prepared by ultrasonic fragmentation. Upon addition of size-controlled fluorescently labeled Res (FLRes) nanoparticles stabilized with DPPG (DPPG-FLRes) to rat skin tissue, FLRes molecules infiltrated into the epidermis layer permeating stratum corneum.

Harmless Effects of Sterilizing 222-nm far-UV Radiation on Mouse Skin and Eye Tissues.

In this issue, Yamano et al. provide further evidence that germicidal 222-nm far UV light has no immediate and delayed harmful effects on the skin and ocular tissue of rats. The safety of 222-nm krypton-chlorine excimer lamps, highlighted in the commentary article, has already received relevant applications in the treatment of surgical site infections and in the control of airborne and foodborne pathogens.

Role of AhR and Foxo1 in skin inflammation in burn animal model via MAPK signaling pathway

Burn generally refers to thermal damage, including tissue damage caused by hydrothermal (water, soup, oil, etc.), flame, steam, high-temperature gas, hot metal liquid or solid (such as molten steel, ingot). However, little is known about the pathogenesis and inducement of skin inflammation in burned rats. Therefore, this study has carried out an in-depth analysis of the related causes of skin inflammation in burned rats. We analyzed the gene expression and the differentially expressed genes co-expression in burned rats. Subsequently, a set of functional dysfunction modules about inflammation of skin tissue in burned rats were obtained by comprehensive enrichment analysis. In addition, based on related network prediction analysis, we identified a number of regulatory factors, such as endogenous genes, nCRNAs, and transcription factors that have potential monitoring effects on skin inflammation in burned rats. Firstly, we obtained 2679 differentially expressed genes and 7 disease-related dysfunction modules in burned rats. Secondly, we identified a series of regulators related to skin inflammation in burned rats, including 117 ncRNAs (including miR-17-5p, miR-122-5p, and miR-140-5p), 31 transcription factors (including AhR, Foxo1 and Sp1) and 10 endogenous genes (including Il5, Atp5d, and Cox4i1). Core transcription factors AhR and Foxo1 may induce skin inflammation in burned rats through the cascade of MAPK signals. According to the results of this study, we can show a new method for biologists and pharmacists to reveal the inducement of skin inflammation in burned rats and provide a valuable reference for different treatment options.

Piceid Nanoparticles Stabilized by Anionic Phospholipids for Transdermal Delivery

Piceid, stilbenoid glucoside, is a representative resveratrol derivative. Because of a high tyrosinase inhibitory activity of piceid through resveratrol derivatives, transdermal delivery of piceid has been desired for taking advantage of the activity. Here we successfully prepared composite nanoparticles composed of anionic phospholipid of 1,2-dipalmitoyl- sn-glycero-3-phosphorylglycerol (DPPG) and piceid by mixing them in water and a subsequent heating/cooling process. When small-sized fluorescently labeled DPPG-piceid (DPPG-FLpiceid) nanoparticles were added to rat skin tissue, FLpiceid molecules were localized in stratum corneum.

Treatment of rat wounds using plasma-jet parameters (Exposure time and gas flow rate)

Worldwide, an estimated millions of patients seek medical care for wounds annually. Different methods and treatment materials have been examined and developed to promote wound healing. Recently, new technology, plasma medicine, has emerged to offer new solutions in wound care. To investigate the efficacy of non-thermal atmospheric pressure plasma jet (NAPPJ) for the treatment of wounds, they were performed 1 cm long and 0.5 cm wide using a surgical scalpel. Treatment was done immediately after the wound operation using an argon plasma jet with different gas flow rates (2.5, 5, 7.5,10 and 12.5slm) and exposure time (3, 6, 9 and 12 min). The treatment was donein a second day. After treatment done the wounds left for one day and in the third day, rat skin tissue has taken and tissue sections had made. The results showed that the mechanical strength of the wound repaired in the plasma treatment group was significantly higher than that in the control group. In addition, evidence from histological studies suggests that wound epithelium is significantly accelerated compared to the control group; vascular and fibrosis (collagen synthesis) increased significantly and the inflammatory stage in wound healing was shorter in the plasma treatment group. The percentage of the necrotic area was higher in the control group than in the plasma treatment group. Furthermore, exposure to voids within the NAPPJ resulted in a significant reduction in the number of neutrophils infiltrated. NAPPJ exposure to interstitials has a positive effect on wounds that lead to wound healing by limiting the progression of the injury.Also, the results show that the speed of gas flow increasesthe wound healing process andthe speed of gas flow increasesthe active species and accelerates the healing process.

Вплив 2-(3-аліл-4-оксо-3,4-дигідро-хіназолін- 2-іл-сульфоніл)-N-(2,6-дихлорфеніл)-цераміду на складові хроматину та стан антиоксидантної системи в саркомі 45 і незмінених тканинах шкіри щурів

Стрімке поширення онкологічних захворювань у ХХІ столітті в усьому світі зумовлює інтенсифікацію хіміотерапевтичного лікування даної патології зі застосуванням усе нових і нових цитотоксичних і цитостатичних агентів. Однак це зумовлює зростання й числа побічних ефектів і небажаних наслідків використання даних препаратів. Неспецифічна дія щодо всього організму пацієнта та висока токсичність даної групи лікарських засобів, зокрема, їхня кардіо-, нефро- та нейротоксичність, а також відсутність достатньої інформації щодо віддалених наслідків введення протипухлинних засобів на стан прилеглих тканин, які не були захоплені інвазією пухлини, зумовлюють нагальну потребу в системному вивченні біохімічних змін не лише в пухлині, але й поза її межами. У попередніх експериментах нами було проведене вивчення впливу протипухлинного похідного хіназоліну на складові хроматину, процеси фрагментації ДНК, вміст небілкових і пов’язаних з білками SH-груп у карциномі Герена та незмінених тканинах матки й виявлено специфічність його впливу на низку показників виключно в тканині пухлини. У зв’язку з цим актуальним є з’ясування, чи є виявлена специфічність похідного хіназоліну характерною лише для тканини матки, чи вона поширюється й на інші тканини організму. Мета дослідження – вивчити вплив 2-(3-аліл-4-оксо-3,4-дигідро-хіназолін-2-іл-сульфоніл)-N(2,6-дихлорфеніл)-цераміду (АХДЦ) на ДНК, РНК, білки хроматину, процеси фрагментації ДНК, вміст небілкових і пов’язаних з білками SH-груп у саркомі 45 і незмінених тканинах шкіри щурів. Тварини були розподілені на 3 групи по 6 тварин у кожній: 1 – інтактні щури; 2 – негативний контроль (саркома 45); 3 – саркома 45 + АХДЦ (29,93 мг/кг). Вивчення впливу АХДЦ на ДНК, РНК, білки хроматину, процеси фрагментації ДНК, вміст небілкових і пов’язаних з білками SH-груп у саркомі 45 і незмінених тканинах шкіри показало, що дана сполука вірогідно змінювала більшість досліджуваних показників як порівняно з інтактними тваринами, так і з саркомою 45 без лікування. Специфічність впливу АХДЦ на клітини пухлин була найвираженішою щодо ДНК-фрагментації та змін вмісту РНК, співвідношень РНК/ДНК і РНК/НК. Щодо впливу на вміст SH-груп у тканині саркоми 45 і неуражених пухлиною тканинах шкіри, то в даному випадку ефект АХДЦ був протилежним за напрямком стосовно змін вмісту небілкових і пов’язаних з білками SH-груп.

The Roles of Skin Fibroblasts at Local Acupoints in Chrono-Acupuncture.

Objective The aim of this study was to demonstrate the peripheral mechanisms of chrono-acupuncture by observing acupuncture at different time points affecting relative proteins to regulate the cytoskeleton of fibroblasts differently. Methods A total of 108 male SD rats (180–220 g) that have basic pain threshold within 3–10 s were selected and randomly divided into group A (n = 72) and control group (n = 36). After the succession of modeling with CFA injection, the rats in group A were randomly divided into model group and acupuncture group, each group containing 36 rats. Then according to the different treatment time, each group was randomly classified into 6 subgroups (ZT0, ZT4, ZT8, ZT12, ZT16, and ZT20), each subgroup containing 6 rats (n = 6). On the second day of successful modeling, the rats in the acupuncture group received acupuncture treatment at the corresponding time point, while the control group and the model group were only tied up at the corresponding time point without any treatments. Methods of operation: use 0.5-inch needles, puncture the rats' “Zusanli” on the affected limb, with Twirling manipulation for a minute after every five minutes; the treatment lasts thirty minutes in total. After 7 days of treatments, the skin and subcutaneous tissue of rats' acupoint area of “Zusanli” on the affected limb were taken and then stained by immunofluorescence double staining method to observe the expression of the fibroblast cytoskeleton F-actin and β-tubulin under the LSCM while using western blot to observe the expression of P38MAPK/P-P38MAPK. Results The expression of the cytoskeleton F-actin and β-tubulin at acupoint area in the acupuncture group was significantly higher than that in the control and model group. The effect of acupuncture on the restructure of the fibroblast cytoskeleton is different at different time points, the most effective time point was at ZT12 while the least at ZT16. Acupuncture can decrease the high expression of P-P38MAPK/P38MAPK in the model group, and the effect has time differences. The expression of P-P38MAPK/P38MAPK increased more significantly at ZT16 than ZT12. Conclusion The remodeling difference of fibroblast cytoskeleton after receiving acupuncture treatment could be one of the peripheral bases of the chrono-acupuncture.

Size-Tunable Paclitaxel Nanoparticles Stabilized by Anionic Phospholipids for Transdermal Delivery Applications

Composite nanoparticles composed of an anionic phospholipid of 1,2-dipalmitoyl-sn-glycero-3-phosphorylglycerol (DPPG) and paclitaxel (PTX) were successfully prepared by mixing them in water followed by a subsequent heating/cooling process. The size of DPPG-PTX nanoparticle could be easily tuned by ultrasonic fragmentation. Upon addition of small-sized fluorescently labeled paclitaxel (FLPTX) nanoparticles with DPPG (DPPG-FLPTX) to rat skin tissue, part of the FLPTX molecules permeated to the stratum corneum.

Effect of pre-acupuncture intervention on serum IgE and cutaneous phosphorylated tyrosine-protein kinase expression in rats with urticaria

To observe the effect of acupuncture on serum IgE level, the degranulation of mast cells, the release of histamine and serotonin, and the expressions of phosphorylated tyrosine-protein kinase Lyn and Syk (p-Lyn, p-Syk) in skin tissue in rats with urticaria, as well as analyze the mechanism of acupuncture in the prevention and the treatment of urticaria. SD male rats were randomly divided into normal control, model control, medication and acupuncture groups (n＝10 in each group). The anti-ovalbumin serum was used to establish urticaria model. Rats of the medication group received gastric lavage of Loratadine (0.1 mg/100 g). In the acupuncture group, bilateral "Xuehai" (SP10) and "Quchi" (LI11) were punctured perpendicularly, about 2 to 4 mm in depth, and the needles were retained for 30 min. The treatment was given consecutively for 14 days in the two treatment groups. H．E. staining was adopted to observe the morphological changes of skin tissue, ELISA to determine the total IgE level in serum, the toluidine blue staining to observe the degranulation of mast cells in local skin tissue and the immunohistochemistry to determine the expressions of histamine and serotonin as well as the the expressions of p-Lyn and p-Syk. Compared with the normal control group, the epidermis of the model control group was significantly thickened, the dermis was swollen, the inflammatory infiltration of small vessels was serious and the mast cells were swollen and deformed, with blurred edge and exfoliated granules. Additionally, in the model control group, the serum IgE level was significantly higher (P<0.05), the expressions of histamine and serotonin, as well as p-Lyn and p-Syk proteins in local skin tissue were significantly increased (P<0.05). Compared with the model control group, in the acupuncture group and the medication group, the epidermis was slightly thickened, the dermis got slightly edema, the inflammatory cells were presented occasionally and the degranulation of mast cells were reduced. Besides, the serum IgE level was significantly decreased (P<0.05), the expressions of histamine and serotonin, as well as the p-Lyn and p-Syk were significantly reduced (P<0.05). There was no significant difference in each index between the acupuncture group and the medication group (P>0.05). Acupuncture at LI11 and SP10 is applicable in the treatment of urticaria. This therapy inhibits the type Ⅰ hypersensitivity and the mast cell degranulation, which may be related to the regulation of p-Lyn and p-Syk protein expressions in the locus coeruleus skin tissue.

Localization and Accumulation Studies of Dacomitinib in Rat Intestines and Skin by Immunohistochemistry.

Dacomitinib, a second-generation tyrosine kinase inhibitor, was irreversible inhibitor forming covalent bonds with the kinase domains of EGFR and other ErbB family receptors. Dacomitinib has been approved for the treatment of locally advanced or metastatic non-small cell lung cancer. In this study, we aimed to develop an immunohistochemistry to detect dacomitinib-ErbB family receptor conjugates. Immunostaining was performed in rat intestine and skin tissues after oral administration of dacomitinib. Following a single oral dose of dacomitinib, strong staining was observed after 24 hr in the ileum and colon, with only slight staining in the duodenum and jejunum. In the skin, strong staining was observed in the epidermis, hair follicles, and sebaceous glands. Moreover, significant amounts of dacomitinib remained for up to 72 hr post-administration in the ileum, colon, and skin. This report is the first to elucidate the localization and accumulation of dacomitinib in the rat intestine and skin and should be valuable during efforts to clarify the mechanism dacomitinib-induced diarrhea or skin toxicities.

The Involvement of SDF-1α/CXCR4 Axis in Radiation-Induced Acute Injury and Fibrosis of Skin.

Radiation-induced acute skin injury and consequent fibrosis are common complications of cancer radiotherapy and radiation accidents. Stromal cell-derived factor-1α (SDF-1α) and its receptor, CXC chemokine receptor 4 (CXCR4) have been shown to be involved in multiple cellular events. However, the role of SDF-1α/CXCR4 axis in radiation-induced acute injury and fibrosis of skin has not been reported. In this study, we found that the expression of SDF-1α and CXCR4 was significantly increased in irradiated skin tissues of humans, monkeys and rats, compared to their nonirradiated counterparts. Mice with keratinocyte-specific ablation of CXCR4 showed less severe skin damage than wild-type mice after receiving a 35 Gy dose of radiation. Consistently, subcutaneous injection of AMD3100, an FDA approved SDF-1α/CXCR4 inhibitor, attenuated skin injury and fibrosis induced by exposure to radiation in a rat model. Mechanically, the SDF-1α/CXCR4 axis promotes pro-fibrotic TGF-b/Smad signaling through the PI3K-MAPK signaling cascade in human keratinocyte HaCaT cells and skin fibroblast WS1 cells. AMD3100 inhibited Smad2 nuclear translocation and transcriptional activity of Smad2/3 induced by radiation, which suppressed the pro-fibrotic TGF-b/Smad signaling pathway activated by exposure. Taken together, these findings demonstrate the involvement of SDF-1α/CXCR4 axis in radiation-induced acute injury and fibrosis of skin, and indicate that AMD3100 would be an effective countermeasure against these diseases.

Genome-Wide Analysis Reveals Zinc Transporter ZIP9 Regulated by DNA Methylation Promotes Radiation-Induced Skin Fibrosis via the TGF-β Signaling Pathway

Radiation-induced skin fibrosis is a detrimental and chronic disorder that occurs after radiation exposure. DNA methylation has been characterized as an important regulatory mechanism of multiple pathological processes. In this study, we compared the genome-wide DNA methylation status in radiation-induced fibrotic skin and adjacent normal tissues of rats by methylated DNA immunoprecipitation sequencing. Radiation-induced fibrotic skin showed differentially methylated regions associated with 3,650 protein-coding genes, 72 microRNAs, 5,836 long noncoding RNAs and 3 piwi-interacting RNAs. By integrating the mRNA and methylation profiles, the zinc transporter SLC39A9/ZIP9 was investigated in greater detail. The protein level of ZIP9 was increased in irradiated skin tissues of humans, monkeys, and rats, especially in radiogenic fibrotic skin tissues. Radiation induced the demethylation of a CpG dinucleotide in exon 1 of ZIP9 that resulted in recruitment of the transcriptional factor Sp1 and increased ZIP9 expression. Overexpression of ZIP9 resulted in activation of the profibrotic transforming growth factor-β signaling pathway through protein kinase B in human fibroblasts. In addition, radiation-induced skin fibrosis was associated with increased zinc accumulation. The zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)-1,2-ethylenediamine abrogated ZIP9-induced activation of the transforming growth factor-β signaling pathway and attenuated radiation-induced skin fibrosis in a rat model. In summary, our findings illustrate epigenetic regulation of ZIP9 and its critical role in promoting radiation-induced skinfibrosis.

Macrophages are necessary for skin regeneration during tissue expansion

BackgroundTissue expansion is a procedure that promotes skin regeneration by mechanical stretch. During the stress and relaxation cycle, the skin undergoes a repeated microtrauma which triggers an immune response leading to the recruitment of macrophages to repair the damaged tissue. Macrophages have been found to be necessary for tissue repair and wound healing, but their effects on skin regeneration during mechanical stretch remain unclear.MethodsThe dynamic changes of macrophages in the rat skin tissues undergoing expansion were quantitatively determined by immunohistochemistry staining. The area of the expanded skin, skin thickness, dermal collagen density, cell proliferation and tissue vascularization were examined to determine the effects of macrophages on the expanding skin. The phenotypes of macrophages and the growth factors related to skin regeneration were also examined to evaluate the underlying mechanisms for the involvement of macrophages in skin regeneration. As a comparison, the tissue samples of expanding skin in which the macrophages were depleted by topically utilizing clodronate liposomes were also evaluated.ResultsThe number of skin macrophages in skin maintained in the high level during the skin expansion compared to non-expanded skin. We found that a switch from an M1- to M2-dominant response during tissue expansion. After the macrophages were depleted, the skin regeneration was inhibited, as evidenced by a smaller expansion area, thinner skin layers and decreased cell proliferation rate, collagen synthesis and, skin vascularization. The secretion of epidermal growth factor (EGF), fibroblast growth factor (FGF), and vascular endothelial growth factor (VEGF) were decreased when macrophages were depleted.ConclusionsOur findings suggest that macrophages are necessary for skin regeneration during tissue expansion. Modulating inflammation may provide a key therapeutic strategy to promote skin growth under mechanical strain.

ULTRASTRUCTURAL EXAMINATIONS ON DIABETIC RAT SKIN TISSUE WITH TOPICAL APPLICATION OF Salvia euphratica ETHANOL EXTRACT

Several medicinal plants to treat diabetic wound healing were researched and are still under investigation. A variety of processes contributed to diabetics such as; inhibition of inflammatory response, generation of reactive oxygen species, differentiation of the extracellular matrix and reduced collagen production . The purpose of this study was to examine the ultrastructural alterations in diabetic rat skin tissue treated with the ointment prepared with Salvia euphratica. Male Wistar albino rats were used in this study (n: 24), divided into 4 groups. Non-treated, diabetic, diabetic and cicatrizant treated, ointment prepared with ethanol extract of 1% Salvia euphratica topically applied for 14 days. A single dose of 45 mg/dL streptozotocin (i.p.) was given to rats to induce diabetes. Excisional wound model was created under anesthesia. A cicatrizant, fitocream, was used as positive control. Normal skin tissue was observed in non-treated group. Diabetic skin tissue revealed hyalinization of the cytoplasm and loss of cytoplasm. Ointment treated diabetic group revealed altered cellular elements suggests healing. At the wound area, number of fibroblast cells synthesizing connective tissue were increased and the collagen fibers were regularly oriented. Neutrophil and monocyte cells besides mast and macrophage cells were found in the capillaries of dermis in S. euphratica ointment treated group. Wound healing in diabetic tissues is known to be slow. Using phytocream therapy to expedite the healing process is a long time known phenomenon. Our observations demonstrated that Salvia euphratica promoted changes in skin tissue that may contribute to wound healing at the cellular level.

Estimation of the postmortem interval using GAPDH mRNA in skin and heart tissues of albino rats at different environmental conditions

Background and objectivesPost-mortem interval (PMI) estimation is an important topic in forensic sciences. Several methods have been used to determine the PMI, but most of these provide inaccurate results under certain conditions. The degradation of RNA after death has been reported to be a useful tool for PMI estimation. This study aimed to evaluate the potential use of skin and heart GAPDH mRNA levels for determining the PMI under different environmental conditions.MethodsSeventy-eight adult female albino rats were sacrificed by cervical dislocation. Then, rats divided into the control group and four experimental groups left under different conditions (in ambient air at 30 °C and at 6 °C, buried in sand and submerged under water at an air temperature of 30 °C). The skin and heart samples were obtained at different time points (0, 24, 48, and 96 h post-mortem), and the GAPDH mRNA level in each sample was detected by qRT-PCR.ResultsThe GAPDH mRNA levels decreased with increasing PMI in all study groups. There were significant negative correlations between the heart GAPDH mRNA level and the time interval in all studied groups, while the skin GAPDH mRNA level only showed negative correlations under certain conditions.ConclusionThe GAPDH mRNA level in rat heart and skin could be a useful marker for PMI estimation under various environmental conditions.