Rapid approach to analyze biochemical variation in rat organs by ATR FTIR spectroscopy.

ATR FTIR spectra were collected from rat tissue homogenates (myocardium, brain, liver, lung, intestine, and kidney) to analyze their biochemical content. Based on the second derivative of an average spectral profile it was possible to assign bands e.g. to triglycerides and cholesterol esters, proteins, phosphate macromolecules (DNA, RNA, phospholipids, phosphorylated proteins) and others (glycogen, lactate). Peaks in the region of 1600-1700 cm(-1) related to amide I mode revealed the secondary structure of proteins. The collected spectra do not characterize morphological structure of the investigated tissues but show their different composition. The comparison of spectral information gathered from FTIR spectra of the homogenates and those obtained previously from FTIR imaging of the tissue sections implicates that the presented here approach can be successfully employed in the investigations of biochemical variation in animal tissues. Moreover, it can be used in the pharmacological and pharmacokinetic studies to correlate the overall biochemical status of the tissue with the pathological changes it has undergone.