Near-Infrared Spectroscopy Correlates with Established Histological Scores in a Miniature Pig Model of Cartilage Regeneration

Abstract

Near-Infrared Spectroscopy (NIRS) could be of clinical relevance in modern cartilage regeneration.In a miniature pig model correlation of measurements and histologic scores have never been used before. The data analysis was part of an animal project that investigated the effects of seeding a chondrogenic and osteogenic scaffold with a bone-marrow-derived cell concentrate and reports the histological and mechanical properties. We created 20 osteochondral defects in the femoral condyles of 10 miniature pigs.The defects were left empty (E), filled with the grafted cylinder upside down (U), or with a combined scaffold (S) containing a spongy bone cylinder covered with a collagen membrane. In the fourth group, the same scaffolds were implanted but seeded with a stem cell concentrate (S+BMCC). The animals were euthanized after 3 months, and histologic and spectrometric analyses were performed. NIRS measurements were significantly higher in the central area of the defects of group S+BMCC compared to the central area of the defects of group U. In all groups, a correlation between NIRS and the histologic scores could be demonstrated though on different levels. In the central area, a good NIRS measurement correlates with low (good) histologic scores. In group E and group S, this negative correlation was significant (p=0.01). For the first time, NIRS was successfully used to evaluate osteochondral constructs in a miniature pig model.

Monitoring the Progression of Spontaneous Articular Cartilage Healing with Infrared Spectroscopy

“…Near-IR analysis permits assessment deeper into the tissue, up to millimeters, and has been used to assess cartilage degradation 58 - 63 and repair. 64 However, the absorbances are very broad, dominated by water, and not well defined with respect to specific molecular species, 46 , 65 so it is not clear whether near-IR alone would be a powerful enough technique to predict a histological grade of repair tissue. Further investigations need to be undertaken to address the true clinical potential of IFOP evaluation of repair cartilage, and should include combined mid-IR and near-IR assessments.…”

Vibrational spectroscopy of articular cartilage

“…A commercial NIR spectroscopic arthroscopic probe has been introduced based on the aforementioned studies. The probe gives a semi-quantitative value between 0 and 100 that represents the cartilage quality (96)(97)(98).…”

Intrinsic fluorescence and mechanical testing of articular cartilage in human patients with osteoarthritis

“…Optical methods, such as optical spectral imaging (OSI) or spectrocolorimetry [13][14][15], diffuse reflectance near-infrared (NIR) spectroscopy [16][17][18] or intrinsic fluorescence [19][20][21][22][23] could potentially provide a non-destructive means of evaluating the state of articular cartilage. OSI has been studied in bovine [13], rabbit [15], and human cartilage [14].…”