화상을 입힌 흰쥐에서 장관내 진균의 전위와 면역능의 변화 = MICROBIAL TRANSLOCATION AND CHANGES OF IMMUNITY IN BURN INJURY

다국어 초록 (Multilingual Abstract)

Sepsis still remains the major cause of morbidity and mortality after initial survival from extensive burn. It has been confirmed that increased translocation of enteric microrganism to the mesenteric lymph nodes and blood flow in association with burn injuries had taken place in otherwise healthy animals. Candida albicans is one of the microflora responsible for sepsis, and its incidence in burned patients has steadily increased. The passage of viable C.albicans through the gastrointestinal mucosa into the host blood stream is believed to be an important mechanism leading to systemic candidiasis.
Several lines of evidence suggest that the immunosuppression of cell mediated immuity(CMI) was due to decreased Th/Ts ratio in burned patients and CMI was specifically suppressed by C. albicans.
The aim of this study is to investigate the relationship and serial changes between the translocation of C.albicans and burn injuries and to clarify the fact that whether the translocation of C.albicans suppress the immunocompetence by observing the changes of lymphocyte subpopulation in burned rats in which the translocation of C.albicans were found. Normal Wistar rats were challenged intragastrically with C.albicans prior to a 40% scald burn in the candida-burn experimental group. Tissues harvested from the mesenteric lymph node, liver, spleen, thymus, jejunum, cecum and colon on the lst, 3rd, 5th＆7th postexperimental days and cultured on Sabouraud dextrose agar and then sitained with periodic-acid Schiff(PAS) to observe the transolcation of C.albicans. Also the lymphocytes were isolated from peripheral blood of the rats at the immediate before the experimentation, lst, 3rd, 5th and 7th postexperimental days and then the subpopulations were measured by flow-cytometry; All findings were compared with those of each control(gavage with phosphate buffered saline(PBS)+shame burn), candida experimental(gavage with C. albicans+shame burn) and burn experimental(gavage with PBS+40% scald burn) groups.
The results were as follows;
1. In the candida experimental group, C.albicans were found to only the mesenteric lymphnode in the early experimental period. In the candida-burn experimental group, the translocation of C.albicans increased more significantly than that of the candida experimental group and the translocation was maintained up to the 7th post experimental day.
2. On microscopic examination, intestinal mucosal atrophy occured after burn injuries. C. albicans seem to have passed through the intestinal mucosal barrier and then they were phagocytized by macrophages in the lamina propria. Also most of C. albicans which had infiltrated into the other organs were phagocytized by macrophages, but some were free. In the candida-burn experimental group, C. albicans were found in the blood vessel of the liver and thymus on the lst postexperimental day and they had infiltrated into the organs at a greater rate than that of the candida experimental group.
3. In the candida-burn experimental group, the Th/Ts ratio was significantly decreased on the 3rd, 5th and 7th postexperimental days compared to that of the pre-experimental day. On the lst and 7th days, such diminution was significant as compared with the control group and on the 3rd, 5th days, the Th/Ts ratio had decreased more significantly than that of the control and candida experimental groups. But at all intervals, no statistical significance was found as compared with the burn experimental group.
With these results it is inferred that burn stress promotes the translocation of C.albicans from the gastrointestinal tract to other organs and the translocation induced by burn injuries is maintained persistantly up to the 7th postexperimental day. And the translocation of C.albicans in burned rats seems not to enhance the depression of CMI through burn injury. But more study will be necessary to understant the immunologic alteration between the translocation of C.albicans and burn injuries.