DMBA and TPA were used for the chemical induction of skin tumor. Furthermore the activity of natural killer cells (NK cells) in spleen and blood were examined. A total of 160 animals were used in this study (5 groups/32 animals each). All animals received a single subcarcinogenic administration of DMBA (10 nmol). Group A (sham-exposed) and group B (daily exposed) were not treated with TPA, whereas group C (sham-exposed) and group D (exposed five days/week) were applicated once weekly with 1 µg TPA. Group E serves as a positive control, without being exposed but treated with 2 µg TPA twice weekly.
Exposure duration: 6 h/day, 5 days/week for 21 weeks
|Exposure duration||6 h/day, 5 days/week for 21 weeks|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||2 mT||-||-||-||-|
Group A and B were used to determine whether the applied magnetic field could act like a classical tumor promoter. No papilloma development could be detected in these groups. Also no significant effect between these groups could be observed concerning NK cell activity.
Group C and D were used to determine if the applied magnetic field (together with the TPA application) could act as a tumor co-promoter. However, no statistically significant difference in tumor development could be found between these groups. The only effect demonstrated by this study was a significantly greater proportion of mice with enlarged spleens and increased number of mononucleated spleen cells in group D compared with the sham exposed group C.