The Effect Of The Wound Healing And Angiogenic Activity In Rat Skin By The Power Extracts From Maggot

Objective:Observed the effect of healing and angiogenic activity in rat wound by the power extracts by Maggot, and to evaluate its relationship and possible mechanisms with wound healing.Materials and Methods:1. Acquire the Maggot powder:Have the Lucilia sericata eggs produced from the fish eyes immersed in 1%sodium sulfite solution, and 3%of the coal phenol soap solution to disinfection, feeding in sterile glass bottles. Take the sterile reared larvae immersed to 3.5%formaldehyde saline solution,2%hydrogen peroxide solution,and 5%hydrochloric acid solution to disinfection. The sterile Maggot will be 40℃drying, mechanical grinding, and the powder has been stored in dryer at room temperature.2. Select 48 healthy male SD rats, weighing 200-220 grams, intraperitoneal anesthesia by 10%chloral hydrate, conventional back skin preparation and iodophor disinfection. In the right and left symmetrical parts of the midline of the rats'back skins, we produced two 1.5cm diameter circular full-thickness skin wounds in acute. The wounds were randomly divided into experimental group (Maggot power group) and control group. Apply the Maggot power 0.3g to the wounds of experimental rats and sterile dressing. Apply the Vaseline 0.3g to the wounds of control group. Dry powder and Vaseline replaced once every other day until the wound healed completely.3. On day 1,3,7,10,14 and 21 after wound creation,8 animals in each group were sacrificed randomly. The wound diameter was measured and the area (mm2) within the boundary was calculated planimetrically. The percentage wound contraction was determined using the following formula:percent wound contraction= (original wound area-unhealed area)/original wound area×100%. Calculated the percentage wound contraction in different time periods of the two groups. 4. In the above time points, the excised wound tissue of the two groups are made Morphology (HE staining) to observe, and to evaluate the wound healing in experimental group and control group.5. Use the Immunohistochemical analysis method to observe VEGFA expression in different time periods of the two groups.6. Analysis of VEGFA mRNA expression by reverse transcriptase polymerase chain reaction (RT-PCR) in different time periods of the two groups.7. Statistical analysis, all the presented data was expressed as mean±standard deviation, and the statistical significances among three groups were analyzed by one-way ANOVA, and then differences among means were analyzed with Fisher's least significant difference t-test using the SPSS version 13.0 software (SPSS Inc., USA). P value less than 0.05 was considered as statistically significant.Results:1. On day 1,3and 14 after wound creation, the percent wound contraction was no significant difference among two groups. On day 7 and 10, the percent wound contraction of experiment group was higher, as compared with control group(P< 0.05). Wounds in two groups healed until day 21.2. Histological examination of excised tissues:On day 1, the wound inflammation of both groups were more obvious; On day 3, showing granulation tissue, epithelial regeneration and vascular response; On day 7, the experimental group have more mature granulation tissue than control group; On day 14, the collagen fibers were arranged regularly, the scar is narrow, and can see the regeneration hair follicles and sebaceous glands in collagen of the experimental group.3. Immunohistochemical examination of VEGFA expression:On day 1,3,7,10,14 and 21, VEGFA expression among both groups, and the expression of both groups decreased over time. On day 3, the VEGFA expression of experimental group are higher than that of control group (P< 0.05).The expression was no significant difference at other time points of both groups(P>0.05).4. VEGFA mRNA expression by RT-PCR:On day 1,3,7,10,14 and 21, the VEGFA mRNA expression in wounds determined by RT-PCR was seen in both groups,and the expression of both groups decreased over time.On day3, the VEGFA mRNA expression of experimental group are higher than that of control group (P< 0.05).The expression was no significant difference at other time points of both groups(P>0.05). Conclusion:1. Maggot powder which used to the skin of rats can increase the percent wound contraction, promote wound healing and improve the quality of wound healing.2. Maggot powder can increase the VEGFA expression in the dorsal skin wounds of rats.3. Maggot power can promote the wound healing in rat dorsal skin may have the relationship with its auxo-action to wound angiogenesis.