Influence of selenium on vascularization in the hamster cheek pouch

The inhibitory effect of selenium (Na2SeO3) on the vascularization induced by amelanotic tumor implants (A Mel-4B32) n the Syrian hamster cheek pouch membrane is reported. Among control animals receiving A Mel-4B32 implants, 19 developed tumors out of 19 chambers with capillary proliferation being observed on day 4 after implant. Addition of 50 microgram Se to the chamber at the time of tumor implant delayed the initial observation of capillary proliferation until day 10 after implant. In the 50 microgram Se treated group, tumor-induced vascularization developed in 11 of 15 chamber implants and not in the remaining 4. Intermediate doses of 5 and 10 microgram Se added to the chamber at the time of tumor implant delayed the initial observation of capillary proliferation to days 7 and 9, respectively, with tumors developing in all chambers. Neither sodium nor sulfite altered the vascular pattern. Capillary proliferation was observed on day 4 after tumor implant when either 50 microgram NaCl or 50 microgram S as Na2SO3 were added to the chamber at the time of implant. Provision of Se as a drinking water supplement also delayed the onset of capillary proliferation.