Imaging of normal and pathologic joint synovium using nonlinear optical microscopy as a potential diagnostic tool

Abstract

An estimated 1.3 million people in the United States suffer from rheumatoid arthritis (RA). RA causes profound changes in the synovial membrane of joints, and without early diagnosis and intervention, progresses to permanent alterations in joint structure and function. The purpose of this study is to determine if nonlinear optical microscopy (NLOM) can utilize the natural intrinsic fluorescence properties of tissue to generate images that would allow visualization of the structural and cellular composition of fresh, unfixed normal and pathologic synovial tissue. NLOM is performed on rabbit knee joint synovial samples using 730- and 800-nm excitation wavelengths. Less than 30 mW of excitation power delivered with a 40×, 0.8-NA water immersion objective is sufficient for the visualization of synovial structures to a maximum depth of 70 μm without tissue damage. NLOM imaging of normal and pathologic synovial tissue reveals the cellular structure, synoviocytes, adipocytes, collagen, vascular structures, and differential characteristics of inflammatory infiltrates without requiring tissue processing or staining. Further study to evaluate the ability of NLOM to assess the characteristics of pathologic synovial tissue and its potential role for the management of disease is warranted.

From molecular structure to tissue architecture: collagen organization probed by SHG microscopy

“…In fact, SHG microscopy highlights morphologic changes in collagen structure, which indicate particular disease states, such as tumour invasiveness, as well as indicators of collagen remodelling in tumour stroma, which is playing a key-role in the tumour development from in-situ to invasive stage. Recently, SHG microscopy has been successfully applied to the study of altered physiological conditions of various kinds of tissues, including muscle [94], bones [95,96], and cartilages [97,98]. SHG can be easily combined with TPEF microscopy to realize a particularly powerful tool for connective tissue imaging.…”

Differentiating the extent of cartilage repair in rabbit ears using nonlinear optical microscopy

“…In recent years, nonlinear optical microscopy (NLOM) has emerged as a promising technique for the quantitative characterization of pathological tissues. This imaging technique has several advantages, including the complete absence of labelling or contrast agents, inherent optical sectioning, subcellular resolution, near-infrared excitation for superior optical penetration and lower photo-damage (Yeh et al, 2005;Tiwari et al, 2010). The greatest advantage of NLOM is the ability to obtain images and spectra of unstained tissue specimens simultaneously, based on the second harmonic generation (SHG) Fig.…”

Multimodal nonlinear microscopy: A powerful label-free method for supporting standard diagnostics on biological tissues

“…[72][73][74][75][76][77][78] SHG microscopy can be used to detect altered physiological conditions in various tissues, including muscle, 79,80 bones 81,82 and cartilages. 83,84 Combined TPF-SHG microscopy provides a powerful tool for imaging both epithelium and connective tissue. In fact, TPF microscopy o®ers high-resolution imaging of NADH in living cells and of elastin within connective tissue, while SHG enables the direct imaging of collagen.…”