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KMID : 0350519940470041821
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Journal of Catholic Medical College
1994 Volume.47 No. 4 p.1821 ~ p.1835
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Effects of Gamma Interferon on the Growth of Ascitic Sarcoma 180 and the Radioprotection of the jejunal Mucosa in Irradiated mice
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Abstract
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To improve local tumor control by irradiation, the radiotherapist is constrained to maximize the tumor dose within the tolerance of adjacent normal tissue. To enhance the radiation cytotoxicity of the tumor and minimize normal tissue damage,
several
methods such as hyperbaric oxygen treatment, high linear energy transfer radiation, and chemical radiation response modifiers have been studied and currently in use. Among these methods, many of published studies focused on radiosensitizers that
selectively sensitize tumor and increase the lethal effects of radiation and radioprotectors that reduce the biological effects of radiation and selectively protect normal tissue. But their clinical applications are limited by potentially severe
toxicity. Several literatures have suggested that interferons may act as a radiosensitizer or radioprotector. Specific biologic actions of interferons, including cell cycle perturbations and cell growth inhibitory effects, suggest that may alter
radiation responses of cells.
The purpose of this study was to investigate the effects of gamma interferon on the growth of ascitic sarcoma-180 tumor cells and the acute damages of the jejunal mucosa in irradiated mice
The experiment was designed to include normal group(no tumor), positive control group(tumor without interferon) and experimental groups(tumor with interferon), which are divided according to the dose of gamma interferon by 500 and 50, 000 unit
gamma
interferon group. Each of groups was subdivided according to whole body irradiation doses by 0, 400 and 900cGy. Malignant ascites was produced in the peritoneal cavity of mice by the innoculation of ascites sarcoma-180 tumor cells. Gamma
interferon
was
administered by subcutaneous injection, every other day from 3 days after innoculation to the end of experiment. For the evaluation of tumor growth, the body weight gain after tumor innoculation was checked and total tumor cell counts in ascitic
fluid
was calculated by hematocytometer. The jejunal mucosal damage was evaluated micorscopically by crypt counts per circumference and histologic damage scoring of the jejunum.
@ES The results obtained were summarized as follows:
@EN 1. In no radiation, 400cGy and 900 cGy radiation groups, significant decrease of total tumor cell counts in ascitic fluid was observed in 500 and 50,000 unit gamma interferon groups, compared with positive control group(P=0.001).
2. There were no significant differences in total tumor cell counts between 500 and 50, 000 unit gamma interferon treatment(P>0.05).
3. Crypt counts in normal control group were 130.33±16.07. In positive control group, 500 and 50,000 unit gamma interferon groups of the no radiation groups, crypt number and histologic damage score were not significantly different from those
in
the
normal control group(P>0.05).
4. In 400 cGy radiation groups, crypt counts of 500 unit gamma interferon groups were significantly increased on 3 and 5 days after irradiation and crypt counts of 50,000 unit gamma interferon groups were significantly increased on 1, 3 and 5
days
after irradiation, compared with no interferon groups(P<0.05). There were no significant differences between 500 and 50,000 unit gamma interferon groups.
5. In 900 cGy radiation groups, crypt counts of 500 unit gamma interferon group interferon groups were significantly increased on 3 days after irradiation and crypt counts of 50,000 unit gamma interferon groups were significantly increased on 1,
3
and
5 days after irradiation, compared with no interferon groups(P<0.05). There were no significant differences between 500 and 50, 000 unit gamma interferon groups.
6. In 400 cGy radiation groups, histologic damage scores of 500 and 50,000 unit gamma interferon groups were significantly decreased on 3 and 5 days after irradiation , compared with no interferon groups(P<0.05). There were significant
differences
between 500 and 50,000 unit gamma interferon groups on 5 days after irradiation(P=0.0086).
7. In 900 cGy radiation groups, histologic damage scores of 500 and 50,000 unit gamma interferon group swere significantly decreased on 1, 3 and 5 days after irradiation, compared with no interferon groups(P<0.05). There were significant
differences
between 500 and 50,000 unit gamma interferon groups on 1 and 5 days after irradiation(P<0.05).
These results suggest that gamma interferon may act as a radiosensitizer on mouse sarcoma-180 ascitic tumor cells and a radioprotector on the jejunal mucosa of the irradiated mice.
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KEYWORD
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