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KMID : 0350519920450041307
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Journal of Catholic Medical College
1992 Volume.45 No. 4 p.1307 ~ p.1319
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Translocation of Enteric Candida albicans and Changes of Lymphocyte Subpopulation in Burned Rats
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Abstract
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Recently the incidence of candida infection in burned patients has steadily increased. The passage of viable Candida albicans through the gastrointestinal mucosa into the host blood stream is believed to be an important mechanism leading to
systemic
candidiasis. A report has confirmed that increased translocation of enteric. C. albicans to the mesenteric lymph nodes in association with burn injuries had taken place in otherwise healthy animals. 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 burnod rat in which the translocation of C. albicans was found. Normal Wistar rats were challenged intragastrically with C. albicans 1 hour prior to a 40% scald burn in the candida-burn experimental group.
Tissues
were harvested from the mesenteric lymph node, liver, spleen, thymus, jejunum, cecum and colon on the 1st, 3rd , 5th & 7th postexperimental day and cultured on Sabouraud dextrose agar and then stained with periodic-acid Schiff(PAS) to observe the
translocation of C. albicans. Also the lymphocytes were isolated from peripheral blood of the rats at the immediate be fore the experimentation, 1st, 3rd, 5th and 7th postexperimental days and then the subpopulations were measured by
flowcytometry.
All
findings were compared with those of each control(gavage with phosphate buffered saline(PBS)+sham burn), candida experimental(gavage with C. albicans + sham burn) and burn experimental(gavage with PBS+40% scald burn) groups.
@ES The results were as follows;
@EN 1. There was no translocation of C. albicans to the mesenteric lymph node or other organs in the control and burn experimental groups. In the candida experimental group, C. albicans was found to only the mesenteric lymph node in the early
experimental period, but there was no evidence of the dissemination of C. albicans to the liver, spleen, or thymus. 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 postexperimental day. The dissemination of C. albicans was evidenced already on the lst postexperimental day. 2. On microscopic examination, intestinal mucosal atrophy occured
after
burn injuries. C. albicans seems 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, some C. albicans were found in the blood vessel of the liver and thymus on the 1st postexperimental day and they had infiltrated into the organs at greater rate than that of
the
candida experimental group.
3. The CD4/CD8 ratio in the candida experimental group was not significantly different from that of the control group and no time course changes were detected. In the burn experimental group, the CD4/CD8 ratio was significantly decreased on the
3rd
and
5th postexperimental days compared to that of the pre-experimental day. That reduction of the CD4/CD8 ratio was significant as compared with the control and candida experimental group. In the candida-burn experimental group, the CD4/CD8 ratio was
significantly decreased on the 3rd , 5th and 7th postexperimental days compared to that of the pre-experimental day. On the 1st and 7th days, such diminution was significant as compared with the control group and on the 3rd and 5th
days, the CD4/CD8 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 understand the immunologic alteration between the translocation of C. albicans and burn
injuries.
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