[The study of an animal model in rabbits with the early primary hyperparathyroidism].

OBJECTIVE: to study the biochemistry of blood and feature of pathology of an animal model in rabbits with the early primary hyperparathyroidism(PHPT). METHODS: 60 rabbits were divided into six groups of 10 each and fed a control diet (Ca:P, 1:0.7) or a high-phosphate diet (Ca:P, 1:7) for 1-, 2- or 3-month intervals. Compared with the control animals, serum PTH levels, serum calcium levels and serum phosphorus levels were determined. The parathyroid and kidneys of all animals were performed by the histologic examination. RESULTS: compared with the control animals, serum parathyroid hormone (PTH) levels were elevated at 1-, 2-, 3-month intervals in experimental group (t = -7.665, t = -16.033, t = 12.877 respective, P < 0.05), whereas serum calcium levels were decreased at all three time intervals (t = 6.184, t = 9.329, t = 13.842, respective, P < 0.05), but serum phosphorus levels did not change (t = 0.611, t = 1.041, t = 1.941, respective, P > 0.05). Parathyroid histopathologic studies demonstrated no change at 1 month whereas six of ten experimental animals showed mild hyperplasia at 2 months and nine of ten showed mild to moderate hyperplasia with gland enlargement at 3 months compared with control animals. Histopathologic examination of the kidneys showed no change at 1 month but focal parenchymal inflammation with calcium deposition at 2- and 3-month in the experimental groups. CONCLUSION: the high-phosphate diet successfully induced an animal model in rabbits with the early primary hyperparathyroidism, which has a better stability and reproducibility.

Bone diseases in rabbits with hyperparathyroidism: computed tomography, magnetic resonance imaging and histopathology.

BACKGROUND: Hyperparathyroidism (HPT) occurs at an early age and has a high disability rate. Unfortunately, confirmed diagnosis in most patients is done at a very late stage, when the patients have shown typical symptoms and signs, and when treatment does not produce any desirable effect. It has become urgent to find a method that would detect early bone diseases in HPT to obtain time for the ideal treatment. This study evaluated the accuracy of high field magnetic resonance imaging (MRI) combined with spiral computed tomography (SCT) scan in detecting early bone diseases in HPT, through imaging techniques and histopathological examinations on an animal model of HPT. METHODS: Eighty adult rabbits were randomly divided into two groups with forty in each. The control group was fed normal diet (Ca:P = 1:0.7); the experimental group was fed high phosphate diet (Ca:P = 1:7) for 3, 4, 5, or 6-month intervals to establish the animal model of HPT. The staging and imaging findings of the early bone diseases in HPT were determined by high field MRI and SCT scan at the 3rd, 4th, 5th and 6th month. Each rabbit was sacrificed after high field MRI and SCT scan, and the parathyroid and bones were removed for pathological examination to evaluate the accuracy of imaging diagnosis. RESULTS: Parathyroid histopathological studies revealed hyperplasia, osteoporosis and early cortical bone resorption. The bone diseases in HPT displayed different levels of low signal intensity on T(1)WI and low to intermediate signal intensity on T(2)WI in bone of stage 0, I, II or III, but showed correspondingly absent, probable, osteoporotic and subperiosteal cortical resorption on SCT scan. CONCLUSION: High field MRI combined with SCT scan not only detects early bone diseases in HPT, but also indicates staging, and might be a reliable method of studying early bone diseases in HPT.