[Histological, biochemical and spectroscopic changes of articular cartilage in osteoarthritis: is there a chance for spectroscopic evaluation?]. / Arthrosebedingte histologische, biochemische und spektroskopische Veränderungen am hyalinen Gelenkknorpel: Welchen Stellenwert hat die spektroskopische Evaluation?

BACKGROUND: Non-destructive techniques for the detection and classification of pathological changes of cartilage in the early stages of osteoarthritis are required for arthroscopic and open surgery of joints. Biochemical and histological changes in cartilage with different degrees of destruction were analysed and correlated to changes in the spectroscopic characteristics of cartilage. PATIENTS, MATERIAL AND METHODS: 24 patients (n = 25 knees) with severely destructed knee joints received total knee replacement. The cartilage of the resected joints was classified according to the ICRS system. Defined cartilage specimens were investigated spectroscopically employing NIRS (near-infrared spectroscopy). In the following the cartilage specimens were harvested to determine the content of proteoglycan (GAG) and hydroxyproline (HP) as an essential part of collagen. Histological evaluation of the Mankin score and Otte score was performed using haematoxylin/eosin and safranin-O staining. Spearman's rank correlation coefficient was used to characterise links between the parameters investigated. RESULTS: We found significant correlations between spectroscopic, histological and biochemical characteristics. NIRS corresponded to the content of GAG (ρ = 0.58) and HP (ρ = 0.59), as well as to the Mankin (ρ = 0.55) and Otte (ρ = 0.5) scores. Furthermore, the ICRS classification correlated with histological evaluation (Mankin score ρ = 0.725 and Otte score ρ = 0.736), as to be expected. CONCLUSION: Characteristic cartilage changes in different degrees of osteoarthritis can be detected and evaluated by the spectroscopic method NIRS as a non-destructive technique. However, the quality of this technical evaluation cannot compete with biochemical and histological analysis.

Applications of autofluorescence for characterisation of biological systems (biomonitoring).

We describe a system capable of measuring the laser induced fluorescence emission of two coenzymes (NADH and FAD) via an optical fibre for in vivo monitoring of anatomical, physiological or pathological changes in biological systems. This optical technique permits the measurement of changes in the metabolism of cells in real-time and is nearly non-destructive. We present results of examinations on the localisation of transitions between different tissue and the monitoring of the oxygenation level (ischemia) in muscle or changes in the cellular activity of bacteria in a bioreactor.