Early detection and monitoring of cartilage alteration in the experimental meniscectomised guinea pig model of osteoarthritis by 99mTc-NTP 15-5 scintigraphy.
OBJECTIVE
This study in the meniscectomised guinea pig aimed to demonstrate that the radiotracer (99m)Tc-NTP 15-5 would have pathophysiological validity for in vivo osteoarthritis imaging.


METHODS
The specificity of (99m)Tc-NTP 15-5 for cartilage was determined in healthy animals (n = 13), by tissue radioactivity counting, joint autoradiography and scintigraphy. (99m)Tc-NTP 15-5 scintigraphy was performed at 20, 50, 80, 115, 130, 150 and 180 days after medial meniscectomy (n = 10 MNX) or sham operation (n = 5), and scintigraphic ratios (operated/contralateral) were calculated for femoral (F) and tibial (T) areas. F and T ratios were compared with those of (99m)Tc-MDP bone scintigraphy. At the study end-point, autoradiographic analysis of joint (99m)Tc-NTP 15-5 distribution and macroscopic scoring of cartilage integrity were performed.


RESULTS
The high and specific accumulation of (99m)Tc-NTP 15-5 in normal cartilage (about 5.5 +/- 1.7 % of injected dose/g of tissue), which permitted joint imaging with high contrast, was affected by osteoarthritis. In the MNX group, (99m)Tc-NTP 15-5 accumulation in cartilage within the operated joint, relative to the contralateral joint, was observed to change in the same animals as pathology progressed. Although F and T ratios were significantly higher in MNX (F = 1.7 +/- 0.2; T = 1.6 +/- 0.1) than in shams (F = 1.0 +/- 0.1; T = 1.0 +/- 0.1) at day 50, they were significantly lower in MNX (F = 0.6 +/- 0.1; T = 0.7 +/- 0.1) than in shams (F = 1.0 +/- 0.1; T = 0.9 +/- 0.1) at day 180. No change in (99m)Tc-MDP uptake was observed over 6 months. Macroscopic analysis confirmed features of osteoarthritis only in MNX knees.


CONCLUSIONS
These results in MNX guinea pigs provide additional support for the use of (99m)Tc-NTP 15-5 for in vivo imaging of osteoarthritis.
Miot-Noirault
Elisabeth
E
INSERM UMR 484, Rue Montalembert, 63005 Clermont-Ferrand Cédex, France. noirault@inserm484.u-clermont1.fr
Vidal
Aurélien
A
Pastoureau
Philippe
P
Bonafous
Jacques
J
Chomel
Agnès
A
Sarry
Laurent
L
Audin
Laurent
L
Madelmont
Jean-Claude
JC
Moins
Nicole
N
D000818:Animals; D002356:Cartilage / Q000000981:diagnostic imaging / Q000473:pathology*; D002357:Cartilage Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D004195:Disease Models, Animal; D042241:Early Diagnosis; D006168:Guinea Pigs; D006573:Heterocyclic Compounds, 1-Ring; D007596:Joints / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology; D008956:Models, Chemical; D010003:Osteoarthritis / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D000644:Quaternary Ammonium Compounds; D011877:Radionuclide Imaging / Q000379:methods*; D013667:Technetium; D013997:Time Factors
D006573:Heterocyclic Compounds, 1-Ring; C407019:N-(triethylammonium)-3-propyl(15)ane-N5; D000644:Quaternary Ammonium Compounds; D013667:Technetium