The Spatial Distribution of Renal Fibrosis Investigated by Micro-probe Terahertz Spectroscopy System.

Renal fibrosis, which is characterized as progressive extracellular matrix accumulation, is a common feature of different stages of chronic kidney disease, and the degree of fibrosis is strongly associated with renal function. In clinical practice, precise understanding of the space distribution of fibrosis is extremely important for the diagnosis and prognosis of renal disease. Rapid advances in terahertz (THz) technology have been made, and this technology has a broad application in bio-detection, as it can interact and measure the collective vibrations and rotations of molecular groups. It is well known that hydroxyproline (HYP) is the key component of collagen, which is synthesized by fibroblasts to maintain the extracellular matrix, and HYP content detection in tissue homogenate can be achieved by classical biochemistry method. In this study, a THz microprobe system was employed to conduct THz microspatial scanning with a resolution of 20 µm. Both the content and distribution of HYP were directly characterized by the THz absorption spectrum. The absorption intensity in the THz spectrum was used to determine HYP density in renal tissues; therefore, the fibrosis change in the kidneys can be determined using THz scanning at micrometer resolution, which provides more possibilities for precise diagnosis of renal fibrosis.