Sixty female nude mice (C578L/6jBom-nu) were injected with 100 microl cell
suspension containing 2 x 10(6) viable cells of an
N-methyl-N-nitroguanidine-induced rat colonic
adenocarcinoma. After seven days the animals were divided into five groups. The first group received only saline and served as a control group. The second group received a triple
therapy of
octreotide,
galanin and
serotonin (20 microg/kg). The last three groups received double
therapies of
octreotide/
galanin,
octreotide/
serotonin or
galanin/
serotonin (20 microg/kg). They were treated twice a day for five days. Tumour volume and weight, relative volume density of tumour-feeding blood vessels and of tumour necrotic tissue, as well as apoptotic and proliferation indices were determined. Animal weight, food consumption, faeces weight and its water content were recorded before and
after treatment. Tumour volume was significantly reduced only in the group that received the triple
therapy. The volume density of the tumour-feeding blood vessels was significantly reduced in the treated groups with the exception of the group that received
octreotide and
serotonin. Increased relative volume density of tumour necrotic tissue occurred only in the group treated with triple
therapy. Apoptotic indices were significantly increased in all treated groups. No statistical difference was found between treated animals and controls regarding proliferation indices, food consumption, faeces weight and water content or animal weight. In conclusion, double
therapy using two of the gastrointestinal bioactive substances,
octreotide,
galanin and
serotonin, has certain effects on
colon cancer cells. To cause a considerable tumour
necrosis, triple
therapy seems to be required. Both double and triple
therapy seem to lack obvious side-effects.