The Effect Of Metallic Derivant Of Taurine On VEGFA Expression During Infected Wound Healing Process In Rats

Objectives:To detect the antibacterial activity of Metallic Derivant of Taurine and study its effect on VEGFA expression during infected wound healing process in rats.Methods:1. Use the MTT assay to examine the in vitro minimum inhibitory concentration (MIC) of Metallic Derivant of Taurine against Staphylococcus aureus. The minimal concentration of the sensitive concentration against Staphylococcus aureus is considered to be the MIC.2. Totally 72 SD rats were accepted one rounded whole-layer skin incision (1.5cm in diameter) on back each other and smeared with Staphylococcus aureus to induce infected wound, and then were randomly divided into two groups:group A (study group,36 rats) topically treated with Metallic Derivant of Taurine liquor lml per wound, and group B (negative control group,36 rats) treated with physiological saline(NS) 1ml per wound. All drugs were applied topically every other day until the wounds completely healed.3. On day 1,3,7,10,14 and 21 after wound creation,6 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%.4. Detect and analyze the bacterial amount in wound tissues between two groups at the above time points.5. The excised wound tissues at different time points were analyzed by histology. Analysis of VEGFA expression by immunohistochemistry, and VEGFA mRNA expression by reverse transcriptase polymerase chain reaction (Rt-PCR).6. 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. The MIC of Metallic Derivant of Taurine against Staphylococcus aureus is 4mg/ml,which had an effective antibacterial activity.2. The percent wound contraction:On day 1 and 3 after wound creation, the percent wound contraction was no significant difference among the two groups. On day 7 and 10, the percent wound contraction of study group was higher as compared with negative control group(P<0.05). Wounds in two groups healed until day 21.3. Histological examination of excised tissues (HE staining):On day 1, the re-epithelialization, granulation and collagen deposition were no significant difference among two groups with a thin and incomplete reepithelialization, abundant fibrinous exudation, few vessels and trace collagen. On day 3, wounds of study group displayed a more accumulation of granulation tissue with a high degree of newly-formed micro-vessels and numerous inflammatory cells and fibroblast. The mean values of parameters related to wound healing in study group were higher compared to negative group (P<0.05) except re-epithelialization. On day 7 and day 10, wounds of two groups demonstrated a continuous epithelial line covering the whole wound bed. Moreover, in study group, the granulation was matured showing capillary vertically oriented, robust fusiform fibrocytes and moderate well-arranged collagen. In contrast, in negative control group, the granulation tissue was un-matured with capillary poorly-organized, many fibroblast and slight collagen formation. On day 21, all the wounds healed, and there was no significant difference among three groups according to histological examination. 4. Immunohistochemical examination of VEGFA expression:On day 3, the MOD, area and IOD of VEGFA expression were at the climax in two groups during the whole healing process. While such men-tioned parameters of study group were higher than that of negative group (P<0.01). On day 7 and 10, the VEGFA expression between two groups has descended, but study group still expressed higher VEGFA than negative group (P<0.05). There was no significant difference at other time points.5. VEGFA mRNA expression by Rt-PCR:On day 3, the VEGFA mRNA expression in wounds determined by Rt-PCR was seen in two groups. Comparatively, the expression of study group was higher than that of negative control group (P<0.05). The VEGFA mRNA expression was no significant difference between two groups at other time points.Conclusions:1. Metallic Derivant of Taurine had an effective antibacterial activity, and the in vitro minimum inhibitory concentration (MIC) against Staphylo-coccus aureus is 4mg/ml.2. Topically applied Metallic Derivant of Taurine on murine infected cutaneous wound can reduce the quantity of microbe and thus facilitate wound healing and improve the quality of wound healing.3. Topically applied Metallic Derivant of Taurine can improve the microvessel density and VEGF expression during wound healing.3. Metallic Derivant of Taurine promoting murine infected cutaneous wound healing is probably resulting from the powerful antibacterial and angiogenic activity of the Cu2+ slowly released from its aqueous solution.