Int J Cancer
1992 Oct 21;52(4):604-8
Radiation-induced
lymphoid tumors and radiation lethality are inhibited by combined
treatment with small doses of zinc aspartate and WR 2721.
Floersheim GL,
Christ A, Koenig R, Racine C, Gudat F.
Department of
Research, Kantonsspital Basel, Switzerland.
Combined small
doses of zinc aspartate and WR 2721 provided additive protection against
radiation lethality in mice.
Survival
obtained with a small dose of WR 2721 which was ineffective alone could
be enhanced to 83% by combining the drug with zinc aspartate, which on
its own also displayed no effect. The survival of 25% provided by a
higher dose of WR 2721 was increased significantly by adding zinc
aspartate.
Additivity was
also tested in a model of radiation carcinogenesis. For this purpose,
lethality and occurrence of lymphoid tumors induced by fractionated
total-body irradiation were studied in C57B1/6 mice treated with zinc
aspartate and WR 2721.
In order to
reveal additive effects, both agents were used at sub-optimal dosages.
In mice subjected to 5 daily exposures of 1.9 Gy, the combination of
zinc aspartate and WR 2721 was effective and enhanced the survival to
83% as compared with 25% afforded by WR 2721 alone (p < 0.005).
Similarly,
histological assessment of organ involvement with lymphoma revealed that
zinc aspartate and WR 2721 alone did not bring about a significant
reduction of lymphoma incidence. On the other hand, the combined agents
diminished organ involvement with lymphoma to 9.1% as against 90% in the
controls (p < 0.0005) and 62.5% with WR 2721 alone (p < 0.025).
Thus, combined treatment with zinc aspartate and WR 2721 also inhibited
radiation-induced lymphoid tumors.
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