Study of blood serum in rats with transplanted cholangiocarcinoma using Raman spectroscopy

Serum samples of healthy rats and rats with inoculated tumors on days 14 and 28 after transplantation of cholangiocarcinoma cells were analyzed using Raman spectroscopy (RS). It was shown that the intensity of the amide 1 band differs in the serum spectra depending on the stage of tumor development and correlates with the protein concentration in the samples. In some animals, there is a significant increase in the blood glucose concentration, leading to glycation of proteins and a change in the shape of the amide 1 band. The appearance of a band at 1670 cm$^{-1}$ is most pronounced in the spectra of samples on the 28th day of the experiment and may be associated with an increase in the content of $\beta$-structural elements in the protein conformation. Using the principal component analysis, we assessed the general differences in the Raman spectra of the blood serum in rats of control groups and rats on the 28th day after tumor transplantation.