Nano silver effectively treats burn wounds in rabbits
We prepared rabbits with boiling water burns with II degree burn models and applied high, medium, and low doses of silver nano hydrogel coating for different times and areas. We then compared the difference in burned paper weight before use and after use in burn models, burns, local skin irritation infections, crusts, and skin scabs over time, and the impact of local skin tissue morphology. The results were a successful rabbit model of deep second degree burns; At days 12 and 18, high, medium and low doses of silver nano hydrogel coating significantly reduced skin irritation of diseased rabbits with integral values (P < 0.01 , P < 0.05 ); High, medium and low doses of nanosilver hydrogel coating group significantly reduced skin irritation, infection integral values (P < 0.01, P < 0.05); High, medium and low doses of nanosilver hydrogel coating significantly reduced the scabbing time on the skin of film-coated rabbits (P < 0.01), significantly shortening the burning time of rabbit skin compared to scabbing time (P < 0.01) and significantly improved the effectiveness of skin disease treatment in rabbits with scald pattern changes (P < 0.01, P < 0.05).
Burns and scalds are common damages, caused by many factors such as physical, chemical, radiation, etc. It is an extremely complex and damaging disease ( Deng et al., 2011 , Muhammad et al., 2017 , Rashid et al., 2017). Burn wound management is an important part of treatment. In addition to surgical treatment, most wound dressings require treatment. Reasonable local wound healing time can directly affect the overall treatment process and results of deep burn wounds. Silver nanoparticles have long-lasting broad-spectrum antibacterial effects, easily generate drug resistance and other properties. Silver nanogels in clinical applications are particularly popular. It can be divided into different types according to different processes. Silver nano gel can treat cervicitis, vaginitis, hemorrhoids, rhinitis and other effects ( Zhou et al., 2011, Yang et al., 2014). Results of investigating the antibacterial effect of silver nano composite membrane – hydrogel on rabbits as a burn model to evaluate the value of nano silver in treating burn wounds.
2 . MATERIAL
2.1 . experimental animals
General level Japanese rabbit provided by Kangda Ha Nam Laboratory Animal Company, animal certification number: 1005365.
2.2 . Medicines and reagents
Silver nano hydrogel wound dressing film, provided by Tongweisuo Research Institute Co., Ltd. of Henan Provincial Academy of Sciences, batch number 20120712-7; Jingwanhong burn ointment, Jingwanhong Tianjin Darentang Pharmaceutical Co. Ltd., batch number 211793; sulfuric acid paper, Zhejiang Minfeng Special Paper Co., Ltd., batch number 20121218; Ethyl carbamate (urethane), recovered from Tianjin Institute of Fine Chemicals, lot number 20120401; Claudel Depilatory Cream, Guangzhou Yibai Ya Cosmetics Co., Ltd., batch number 20110321; Medical absorbent gauze bag, Ha Nam Day Sanitary Supplies Co., Ltd., batch number 20120603; HL-RA medical plaster, Xuzhou Hongli Sanitary Materials Co., Ltd. batch number 20121022; Sodium Chloride Injection, Chen Xin Pharmaceutical Co., Ltd., lot number 1208308201; Formaldehyde solution, Yantai shuangshuang Chemical Co., Ltd., lot number 20121012.
3 . METHOD
3.1 . Sample
We took healthy Japanese rabbits 36, 2.0–2.5 kg, male and female. After shaving both sides of the rabbit’s back with Claudel smart hair removal cream, we removed the rabbit’s hair over an area of approximately 20 cm × 15 cm; The next day, 30 people were taken as samples, anesthetic injection of 20% urethane (1 g/kg) was injected into the ear vein, and their limbs were placed in a prone position. They are fixed on the operating table with rubber bands. We put the cotton pad package (18 layers) weighing 200 g, diameter 1.8 cm into boiling water at 100 degrees Celsius to absorb. After boiling, we immediately put them on the left and right sides of the spine skin preparation area, each pressure 20 s, from front to back on each side of each three circular hot wound, leading to a total of 6 wounds per animal. Wound diameter 1.8 cm, area about 2.54 cm 2, deep burn pattern II (biopsy confirmed). Immediately after, we intraperitoneally injected sterile saline 20 mL/suture in some of those models ( Wu et al., 2011 , Miao et al., 2016 , Wang et al., 2016 , Razali and Said, 2017 ).
3.2 . Grouping and management
The next day after burns with sulfuric acid paper, graphic drawings of the burned skin, we observe the quality of the drawings, taken from the burned area on an electronic scale to indicate the quality of burns on the skin ( Miao et al., 2012 , Mi et al., 2014). The burn area of the animals was different due to the difference in operation, so we divided them into groups, namely the model group, the Jingwanhong group, and the large, medium, and small dose nanosilver hydrogel-coated film groups. , a total of six groups. The remaining six people formed a control group. After modeling, each group of rabbits will be given appropriate medicine. Large, medium, and small doses of silver nano hydrogel films were applied topically for each dose group. Jingwanhong group applied Jingwanhong burn cream (thickness 2 mm). Control group, model group, free saline in each group after using the above was wrapped with plastic wrap and firmly taped, with regular uninterrupted dosage to maintain continued medication Contact with skin for 6 hours a day and use the medicine continuously for 18 days.
3.3 . Experimental index
Test criteria: infection at the burn site, general condition, pathology. Burn area: apply sulfuric acid on burn paper to the first ulcers 1, 6, 12, 18 d along the wound. We measure and draw the burned skin area. Changes in weight indicate changes in burning skin. We used the weight of the paper before administration to subtract it after treatment to evaluate the effect of the experimental drug ( Wang et al., 2014 , Shamsudin et al., 2017 , Zaheer et al., 2017) . Burning local tissue pathology: the next day after the last dose, carry out a histopathological examination of the drawn out, cut the burned skin sections, fix them in 10% formalin solution and cut into paraffin-embedded sections . Its staining was observed to compare the burns of each group of rabbits to observe the degree of skin healing.
3.4 . Statistical analysis methods
Data were analyzed using Windows SPSS 17.0 statistical software. The differences of measurement data between groups were analyzed using ANOVA.
4 . RESULT
4.1 .
Effect of silver nano hydrogel coating on rabbit burn model ( x ± s)
From table 1 it can be seen that, compared to the blank group, the difference in paper weight on the skin in the model group is significant (P < 0.01), which shows that the rabbit burning model was successful. Compared with the model group, on day 6, the high and low dose nano silver hydrogel coated burn groups and the difference in paper weight on the skin area of Jingwanhong rabbits increased significantly (P < 0.05 ) ; on day 12, the average dose of nanosilver hydrogel coating group and Jingwanhong rabbit burned skin area of paper weight difference was significantly increased ( P < 0.05); On the 18th day, the average dose of silver nano hydrogel film coated rabbit group, the area of burned rabbit skin and the paper weight difference was significantly increased (P < 0.05).
4.2 . The burned nano silver hydrogel film irritates the skin locally at the rabbit’s infected spots
As can be seen from Table 2 , on day 3, the high, medium and low dose nanosilver hydrogel coating groups and the integrated value of infected skin irritation of Jingwanhong rabbits decreased significantly ( P < 0.05 ) ; On day 6, the high-dose nanosilver hydrogel coating group significantly reduced rabbit skin irritation with an integral value (P < 0.01), the high-dose nanosilver hydrogel coating group significantly reduced rabbit skin irritation contamination of the integral value ( P < 0.05) ; on the 12th and 18th days of treatment, the skin irritation infections of each group of rabbits disappeared.
4.3 . Effects of nano silver hydrogel coating on scars and scabbing time on rabbit skin
From table 3 it can be seen that the skin in the white and normal groups, the group with the scaly appearance pattern and scabbing time; Compared with the model group, the medium and low dose nanosilver hydrogel coating group and the Jingwanhong group could significantly shorten the scabbing time on the skin of burned rabbits ( P < 0.01); high, medium, and low dosages of nanosilver hydrogel coating group and Jingwanhong group could significantly shorten the scabbing time on burned rabbit skin ( P < 0.01).
4.4 . Effect of nano silver hydrogel coating on local tissue morphology on rabbit skin
As can be seen from Table 4 , after the Ridit test, compared with the blank group, there were significant pathological changes in the skin of the model group rabbits. Compared with the model group, the high and medium dose nanosilver hydrogel coating groups could significantly improve the skin pathological changes on the burn model ( P < 0.01).
“−”: Keratosis, squamous epithelium, hair follicles, follicular glands, sebaceous glands, and normal subcutaneous tissues; “+”: thinner keratinized layer, mild squamous epithelial hyperplasia, partially denatured small adenoid cysts, mild sebaceous cell proliferation, subcutaneous tissue, normal; “++”: thickening of the stratum corneum and release of a small amount of inflammatory cells, squamous epithelial hyperplasia, partial denaturation of hair follicles, replacement of hair follicle glands, phosphate sebaceous glands, and subcutaneous granulation tissue; “+++”: the stratum corneum thickens and secretes inflammatory cells, the squamous epithelium increases markedly, hair follicles degenerate, hair follicles, sebaceous glands disappear, subcutaneous tissue is replaced by a large amount of granulation tissue.
Each group of rabbits reburned the results of local tissue morphology appendix: animal control group stratum corneum of epithelial tissue and intact squamous epithelial cells and thin subcutaneous tissue and hair follicles of hair follicles and sebaceous glandsnormal, also under normal skin, see photo 1; Animal model group tested the stratum corneum of the epithelium, squamous epithelium completely denatured, subcutaneous tissue, hair follicles and sebaceous glands and hair follicles denatured and disappeared. The subcutaneous tissue is replaced by a large amount of granulation tissue, see photo 2; In the Jingwanhong group, some experimental animals had thickened epithelial tissue with keratinization, squamous epithelial hyperplasia, and significant exudative inflammatory cells. The subcutaneous tissue of hair follicles, sebaceous glands, and hair follicles was phosphate; The stratum corneum of some animal epithelial tissues disappears. Squamous epithelial hyperplasia and hair follicles are completely denatured. Subcutaneous tissue, hair follicles and sebaceous glands disappear. The subcutaneous tissue is replaced by a large amount of granulation tissue, see photo 3; Large doses of nano silver hydrogel coating were tested on animals with leaking keratinized epithelium. Large amounts of inflammatory cells are replaced by somewhat squamous epithelial hyperplasia. The hair follicle subcutaneous tissue, sebaceous glands and hair follicle epithelial cells disappear, replaced by a large amount of granulation tissue, see photo 4; The stratum corneum of the animal group’s Nano-silver hydrogel-coated epithelium. The squamous epithelium is replaced by the disappearance of many inflammatory cells and tissue degeneration, the subcutaneous tissue, hair follicles, sebaceous glands and hair follicles disappear, The subcutaneous tissue is replaced by a large amount of granulation tissue, see photo 5; Nano-silver hydrogel small dose group of animals covered by the stratum corneum of the epithelium. Squamous epithelium disappears; Many inflammatory exudate and degenerative tissue cells replace the tissue under the skin of the hair follicle. Sebaceous glands and hair follicles disappear. The subcutaneous tissue is replaced by a large amount of granulation tissue, see photo 6.
5. conclusion
Burn wounds are more open wounds and can easily become infected by breeding bacteria. Antibiotics are often used in clinical practice. With the increasing diversity of clinical overuse of antibiotics and drug-resistant strains in skin and wounds, the use of a simple antibiotic therapy is unlikely to achieve the desired results. Methods for treating burn wounds locally are very diverse, but how to control the use of topical burn wound medications appropriately and effectively is still being hotly discussed (Li et al., 2016 )). Modern medicine believes that, after a burn, local skin tissues will function poorly, leading to local wound microcirculation, insufficient blood supply, stagnant edema and necrosis, and at the same time due to The skin’s protective barrier function is damaged, so inflammatory secretions increase. This can easily lead to bacterial infection. And the use of silver Nano particles and bacterial protein thiol groups (-SH) bind, causing their degradation, so the inactivation of sulfhydryl enzyme has a broad-spectrum antibacterial effect, in when Nano silver wound matrix metalloproteinase has an inhibitory effect. This advantage greatly contributes to wound healing ( Shi et al., 2014 , Gao et al., 2017 ). Nano silver is a new generation natural non-antibiotic fungicide, with stable physical and chemical properties and broad-spectrum bactericidal ability ( Liu et al., 2009 , Liu, 2016 ). Nano silver has strong permeability, can quickly penetrate into skin pores, kill a variety of bacteria, fungi, mycoplasma, chlamydia and other bacteria within minutes, and bacteria are resistant to silver. is extremely rare, thus obtaining many medical biological applications.
The experiment chose the difference in paper weight of the local burned skin area as the main appearance index, because it is visible; Histopathological changes reflect the deterioration of the layered organization of damaged and healed skin. Choosing local pathological tissue as an objective index can help us better estimate the extent of scald modeling ( Li et al., 2013 , Liang et al., 2013 ). The above indices correspond from two aspects of disease and quality, providing a comprehensive assessment of the healing effect of the topically applied Nano silver hydrogel mixture on the rabbit burn model.
Experimental results showed that the group coating a small amount of Nano silver gel could reduce the burn area of rabbits, avoiding edema and burn infection. The time for local burn scabs to form is significantly shortened. Silver nano gel can significantly improve the skin pathological changes of the burned skin of rabbits, indicating that it has a certain therapeutic effect on the burned skin. Therefore, the experiment using Nano silver gel film to treat scalds and clinical burns proves that this is a simple, effective and controllable treatment method.
