Changes of NOS Activity and NO Content in Rectal Cancer Tissues

Abstract

Nitric Oxide (NO) plays important role in many pathological processes (inflammation, infection, cell death, neoplastic disease, cirrhosis, diabetes, intestinal disease) and normal physiological processes (blood pressure regulation, neurotransmission, wound healing, host defense mechanisms). we aimed to investigate the relationship between changes in NOS activity and changes in NO content in cancer tissues according to the histopathological classification of rectal cancer. The study population included 102 rectal tissue from rectal cancer patients over the past three years and 33 rectal autopsy specimens from those who had not experienced any inflammatory or neoplastic disease in the past. The activity of NOS in rectal tissue was determined by the Griess’ method and the citrulline assay for NO production, and the NO content was determined by the Griess’ method.  Histopathological examination of histotype, depth and differentiation was performed on microscopic images, and the histopathological parameters of rectal cancer were compared with the changes in NOS activity and NO content in the cancer tissues and t-tests were performed. The changes in NOS activity and NO content in rectal cancer tissues are as follows. In rectal cancer, NOS activity and NO content in cancer tissues were significantly higher than those in healthy controls (0.076±0.002μmol/min and 5.84±0.17μmol/g, significantly) with 0.16±0.01μmol/min  and 15.63±0.64μmol/g, significantly. In the histopathological classifications (macroscopic pattern, histotype, depth, and differentiation) in rectal cancer, NOS activity and NO content decreased according to the classification.