OBJECTIVETo evaluate the inhibitory of profrin II nanoparticles photodynamic therapy on Lovo human colon cancer xenografts in athymic mice.

METHODSProfrin II nanoparticles were obtained from hypersound emulsification method. LOVO human colon cancer xenograft were established in athymic mice. Athymic mice were divided into four groups:normal control group, profrin II nanoparticles control group, profrin II PDT group and profrin II nanoparticles PDT group. The animals bearing xenografts were treated 30 mg/kg body weight profrin II nanoparticles and 3 h later were irradiated with 9 J/cm(2) light from a diode laser. After Profrin II nanoparticles PDT, the anti-tumor effect was assessed by measuring tumor volume over a 3-4 weeks period, the morphologic changes were observed by microscopy and microscopy via the histological examination.

RESULTSCompared with the control groups, profrin II nanoparticles control group, profrin II PDT group and profrin II nanoparticles-PDT treated tumors had regressed significantly in earlier period with the inhibiting rate being 87.9% (P<0.05), 87.5% (P<0.05) and 56.0% respectively (P<0.05). In the later period post-PDT, tumors growth resumed with a slower rate. Profrin II nanoparticles-PDT prolonged the survival time in the treated group with (38.0+/-6.0) days (P<0.05). Extensive damage to tumor tissue was found in the earlier period (7d) post-PDT, whereas in the later period (21d) post-PDT, islands of vital-looking tumor cells were observed around the damaged tissue.

CONCLUSIONProfrin II nanoparticles-PDT results in inhibition Lovo colon carcinoma growth in post-PDT earlier period in vivo, and can prolong the survival time of nude mice bearing xenografts significantly, whereas profrin II-PDT could not inhibit the growth of colon tumor completely.