Ito H, Komaki R, Milas L. Protection by WR-2721 against radiation plus cis-diamminedichloroplatinum II caused injury to colonic epithelium in mice.
Int J Radiat Oncol Biol Phys 1994;
28:899-903. [PMID:
8138443 DOI:
10.1016/0360-3016(94)90110-4]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE
The study was designed to investigate the ability of S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR-2721) to protect mouse colon mucosa against damage produced by the combined radiation plus cis-diamminedichloroplatinum II (cis-DDP) treatment.
METHODS AND MATERIALS
The mucosal damage was quantified by using microcolony assay, which measures the survival of epithelial cells in colon crypts. Radiation doses ranged from 8-24 Gy gamma rays. Cis-diamminedichloroplatinum at a dose of 13 mg/kg and WR-2721 at a dose of 400 mg/kg body weight were given IP before or after irradiation.
RESULTS
Addition of cis-DDP to radiation within 24 h before and 48 h after irradiation reduced the number of crypt cells more than did radiation alone. The highest reduction was seen when the drug was given 2 or 6 h before irradiation: the damage was increased by a factor of 1.5. Protective effects of WR-2721 were tested in the radiation plus cis-DDP combination in which cis-DDP was given 2 h before or 2 h after radiation. In the former sequencing, WR-2721 was given 30 min before radiation (90 min after cis-DDP); damage was reduced more than the amount of damage contributed by cis-DDP (PF = 1.6). When cis-DDP was given 2 h after irradiation, WR-2721 was administered 30 min either before irradiation or 30 min before cis-DDP. Here, the protective effect was achieved only when WR-2721 was given before radiation: the PF was 1.3 in that case and only 1.1 when WR-2721 was given before cis-DDP. Thus, WR-2721 must be given before irradiation, but even then the degree of protection achieved depends on whether cis-DDP is applied before or after irradiation, with the protection being greater in the former situation.
CONCLUSION
Our observations showed that WR-2721 is a potent protector against the injury of mouse colon mucosa produced by the combined radiation plus cis-DDP treatment. They have important implications in the clinic, indicating that proper timing of WR-2721 administration is crucial for preventing side effects of the cis-DDP and radiotherapy combination, where damage to mucosal epithelial cells is dose limiting.
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