LIGHT MICROSCOPE AND IMMUNOHISTOCHEMICAL STUDY FOR WOUND HEALING MECHANISM OF RAT SOFT TISSUE

ABSTRACT

Once tissue are injured by certain causes, our body can't maintain a normal biologic rhythm, and because of this, wound healing responses start right after the injury. The healing process can be divided into four stages 1) inflammatory phase 2) epithelialization phase 3) proliferation phase 4) maturation phase. Each phase is overlapped and continued without any apparently distinguishable characteristics. The factors affecting on wound healing are wound management, nutritional element, environment factor, and existence of other diseases. This research was focused on overall examination of tissue alteration on each stage of wound healing by artificially designing skin defect on rats so that the result from the examination could be easily applied to clinical activity. To do this, After the hair on the dorsal surface was shaved, 15x8mm oval skin defect was formed. The rats were examined intensely on the 3rd, 7th, 15th, 21st day, and were sacrificed on the 30th day. After fabricating 4micrometer paraffin specimen, H-E staining, MT staining, immunohistochemical study using PCNA and alpa-SMA were performed respectively. The outcomes were as follows 1. On the 3rd day, severe edema, and acute inflammatory reaction were seen. Collagen deposition and blood vessel proliferation were started from the 7th day. On the 15th day, collagen deposition was increased and new blood vessel proliferation was intensified. 2. Acute inflammatory reaction was completely disappeared and collagen deposition was critically increased on the 21st day. Re-epithelialization observed from the 21st day reached at the nearly normal status on the 30th day. 3. In the control group, PCNA positive reaction was seen on the basal layer and hair follicle of epidermis ; however, in the experimental group, PCNA positive reaction was increased on the basal cell layer and hair follicle as re-epithelialization occurred. 4. Blood vessel proliferation observed by alpa-SMA positive reaction was the most intense on the 15th day, and as time went by, the proliferation decreased. As re-epithelialization was continued, alpa-SMA positive reaction increased on the basal cell layer of epidermis and surrounding hair follicle. According to the above results, it was confirmed that the re-epithelialization of rats began on the 21st day when inflammatory reaction was disappeared and, on the 30th day, it was recovered to the stage similar to a normal status. This kind of recovery from skin defect started with re-epithelialization on the basal cell layer and surrounding hair follicle.