A fluorescent probe may make it easier to diagnose and monitor osteoarthritis, according to a study published in the February issue of Arthritis & Rheumatology. Researchers found that a fluorescent probe tracked the development of osteoarthritis in male mice, brightening as the disease progressed. Their study is the first to demonstrate that near-infared fluorescence can be used to detect osteoarthritis changes over time.
“Patients are frequently in pain by the time osteoarthritis is diagnosed. The imaging tests most frequently used, x-rays, do not indicate the level of pain or allow us to directly see the amount of cartilage loss, which is a challenge for physicians and patients,” said lead author Averi A. Leahy, BA, an MD/PhD student in the medical scientist training program at Tufts University School of Medicine (TUSM) and the Sackler School of Graduate Biomedical Sciences at Tufts in Boston.
Averi A. Leahy
For this study, the right knees of 54 mice were affected by injury-induced osteoarthritis and served as the experimental group. The healthy left knees of the mice served as the control group.
Over a 2-month period, the researchers took images of each knee every 2 weeks to determine if the fluorescent probe emitted a signal. The signal became brighter in the injured right knee, at every examined time point, through the early to moderate stages of osteoarthritis. The probe emitted a lower signal in the healthy left knee, and did not increase significantly over time.
According to the researchers, the fluorescent probe made it easy to see the activities that lead to cartilage breakdown in the initial and moderate stages of osteoarthritis, which is necessary for early detection and adequate monitoring of the disease.
Senior author Li Zeng, PhD, an Associate Professor in the Department of Integrative Physiology and Pathobiology at TUSM and member of the cellular, molecular, and developmental biology program faculty at the Sackler School reported that the next step is to monitor the fluorescent probe over a longer period of time to determine whether the same results are produced during the late stages of osteoarthritis.