Accumulation of porphyrin metabolites induced by 5-aminolevulinic acid in urine of rats with colorectal cancer / 中国医师杂志

ABSTRACT

Objective:To investigate the accumulation of porphyrin metabolites [uroporphyrinogen (UP) Ⅰ and coproporphyrinogen (CP) Ⅲ] induced by 5-aminolevulinic acid (5-ALA) in the urine of rats with colorectal cancer.Methods:The rat model of colorectal cancer was established by dimethylhydrazine (DMH). Urine samples were collected from 30 colorectal cancer rats (colorectal cancer group) and 30 normal rats (normal group). Each animal was given 5-ALA (50 mg/kg) by gavage, and urine was collected after 2, 4, 6 and 8 h. The contents of urinary porphyromogen Ⅰ and porphyromogen faecalis Ⅲ in urine were detected by high performance liquid chromatography (HPLC).Results:There was no significant difference in the contents of UP Ⅰ and CP Ⅲ in urine between colorectal cancer group and normal group before oral administration of 5-ALA ( P>0.05). After oral administration of 5-ALA, the contents of UP Ⅰ and CP Ⅲ in urine of colorectal cancer group were significantly higher than those of normal group ( P<0.05). The contents of UP Ⅰ and CP Ⅲ in urine of colorectal cancer group reached the highest value at 4 hours. According to the receiver operating characteristic (ROC) curve drawn from 4-hour test results, the threshold value of UP Ⅰ for colorectal cancer diagnosis was 50.43 μmol/g, with corresponding sensitivity 96.7%, and the specificity 63.3%, respectively. The threshold value of CP Ⅲ for colorectal cancer diagnosis was 108.85 μmol/g, with corresponding sensitivity 66.7%, and the specificity 86.7%, respectively. Conclusions:The accumulation of porphyrin metabolites induced by 5-ALA in the urine of rats with colorectal cancer is significant. The porphyrin metabolites in urine may be a new tumor marker of colorectal cancer, which provides an experimental basis for the diagnosis of colorectal cancer.