Effects of ethane-1-hydroxy-1,1-diphosphonate on ossification of the posterior longitudinal ligament in Zucker fatty rats.
OBJECTIVE
Using Zucker fatty rats as an animal model, we evaluate the effectiveness of ethane-1-hydroxy-1,1-diphosphonate on ossification of the posterior longitudinal ligament by histopathologically investigating the prodromal, early, and advanced stages of ossification of the spinal ligaments.


METHODS
73 Zucker fatty rats were allocated to the ethane-1-hydroxy-1,1-diphosphonate group (n=33) and the control group (n=40). The former group was fed ethane-1-hydroxy-1,1-diphosphonate daily. The feed was given starting 2 months after birth and continued until the rats were killed at 3 to 18 months later. Chemical analysis of the blood, radiographic tests, and histopathological examination were then conducted for both groups.


RESULTS
The results showed that ossification of the spinal ligaments involved excessive cartilage cell proliferation around areas affected by enthesitis; enlargement of the fibrocartilage tissue layer; ligament thickening; calcification of the matrix around the cartilage cells; and ossification of the spinal ligaments through enchondral ossification. Radiographic examinations showed that osteoproliferation in vertebral bodies in rats receiving ethane-1-hydroxy-1,1-diphosphonate was generally suppressed compared with controls, whereas histopathological examinations found no clear difference in cartilage cell proliferation in areas affected by enthesitis between the two groups, indicating the absence of calcification or osteo-proliferation in areas affected by enthesitis for the rats receiving ethane-1-hydroxy-1,1-diphosphonate.


CONCLUSIONS
Ethane-1-hydroxy-1,1-diphosphonate is effective in suppressing progressive ligament ossification.
Yamamoto
K
K
Department of Orthopedic Surgery, Tokyo Medical University, Tokyo 160-0023, Japan. kengo-y@tkg.att.ne.jp
Imakiire
A
A
Shishido
T
T
Masaoka
T
T
D000818:Animals; D001707:Biopsy, Needle; D004195:Disease Models, Animal; D012968:Etidronic Acid / Q000494:pharmacology*; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D017887:Ossification of Posterior Longitudinal Ligament / Q000188:drug therapy* / Q000473:pathology*; D011897:Random Allocation; D051381:Rats; D011924:Rats, Zucker; D012016:Reference Values; D012680:Sensitivity and Specificity
D012968:Etidronic Acid