ABSTRACT
<p><b>OBJECTIVE</b>To investigate effects of Sargassum confusum polysaccharide (SP) on the expressions of p53 and Rb genes.</p><p><b>METHODS</b>The mice bearing S180 sarcoma were treated with abdominal SP injection at the daily dose of 50, 100 or 200 mg/kg for 10 consecutive days, The mice injected with 0.85% saline served as the negative control group and those with 5-fluorouracil (5-FU) injection as the positive control group. The tumor weight was measured to calculate the tumor inhibition rate. RT-PCR and Western blotting were used to detect the expression levels of p53 and Rb genes at the mRNA and protein levels, respectively.</p><p><b>RESULTS</b>The 10-day SP treatment at 50, 100 and 200 mg/kg resulted in tumor growth inhibition rates of 30.5%, 47.6% and 63.5%, respectively. SP treatment upregulated the mRNA expressions and increased the protein levels of p53 and Rb in the tumors.</p><p><b>CONCLUSION</b>SP has inhibitory effect against S180 sarcoma in vivo and can increase the expression levels of p53 and Rb genes at both the mRNA and protein levels.</p>