effects of 8 weeks of resistance training and igf-1 injection on biochemical markers of cancer and colorectal structures in rats

Background and objectives: we studied effects of eight weeks of resistance training and igf-1 injection on serum level of igf-1, igfbp-3 and igf-1/igfbp-3 ratio in wistar rats. methods: we randomly divided 28 male wistar rats into four groups of salineinjected control (c), resistance training+saline injection (rs), resistance training+igf-1 injection (ri) and igf-1 injection (ii). resistance training protocol consisted of climbing a ladder (three days/week with 5 reps/3 sets) while carrying a weight suspended from the tail for eight weeks. igf-1 and saline (1.5 μg/kg/day) were injected before and after exercise sessions. serum igf-1, igfbp-3 and igf-1/igfbp-3 ratio and morphology of colorectal tissue were evaluated. results: serum igf-1 level and igf-1/igfbp-3 ratio decreased in the rs group compared to the other groups (p< 0.05). rats in the rs group had higher igfbp-3 level than those in the ii and ri groups (p< 0.05). igf-1 injection had no effect on morphology of colorectal tissue. conclusion: the resistance training reduces igf-1 and increases igfbp-3 levels, which might represent a link between resistance training and lower risk of colorectal cancer.