ABSTRACT
Objective:To investigate the distribution of 99Tc m-methylene diphosphonate (MDP) at different stages of bone injury repair. Methods:A total of 30 rabbit models of femur injury were established by the method of electric drill and perforation of femur. According to the different stages of bone injury repair (at 1, 2 and 3 week), rabbits were divided into group A, B and C ( n=10 each group). Femoral SPECT/CT imaging was performed on the last day of different stages of bone injury repair to obtain radioactivity counts in the region of interest (ROI) on the test side and control side and to calculate target/background ratio (T/B). The light intensity of 3 groups was analyzed by phosphor screen imaging and the distribution of 99Tc m-MDP in bone cells was observed by autoradiography. One-way analysis of variance and paired t test were used to analyze the data. Results:The T/B values of group A, B and C were 1.16±0.14, 1.39±0.23 and 1.18±0.10, respectively ( F=5.83, P<0.01). There were significant differences of the maximum radiation count between the test side (50.00±12.45, 59.50±12.83 and 55.10±9.26) and the control side (43.20±9.57, 50.00±12.30 and 44.30± 6.50) in group A, B and C ( t values: 3.24, 2.28 and 5.77, all P<0.05). There were significant differences in the light intensity of bone specimens in group A, B and C by phosphor screen imaging (37 324.67±6 481.50, 60 950.33±9 781.72 and 43 905.00±4 957.92; F=8.25, P=0.02). 99Tc m-MDP were deposited in both intracellular and extracellular during different stages of bone repair in osteocytes and osteoblasts under autoradiography. Conclusion:At different stages of bone injury repair, the concentration of 99Tc m-MDP is significantly distributed, suggesting that there are other ways of concentration mechanism of 99Tc m-MDP in bone tissue besides the chemical adsorption with hydroxyapatite.
ABSTRACT
AIM: Occlusion of the middle ferebral artery in rats may cause secondary injury that is not associated with middle ferebral artery feeding zone. This entity has been investigated very rarely. MATERIAL AND METHODS: HE staining method observed the changes of cerebellar cortex after MCAO operation. Electron Microscopy and TUNEL methods observed the apoptosis of neural cells of cerebellar cortex after MCAO in rats. Immunohistochemical analyses method observed the caspase-3 in neural cells of cerebellar cortex. RESULTS: The results of HE staining indicated that no ischemia-necrosis changes of cerebellar cortex tissue were observed after MCAO operation by HE staining. Further experiments by Electron Microscopy and TUNEL assay revealed that the apoptosis of neural cells of cerebellar cortex were induced after MCAO in rats. Furthermore, immunohistochemical analyses showed that caspase-3 played an important role on MCAO-induced apoptosis of neural cells of cerebellar cortex. CONCLUSION: These data showed for the first time that the role of caspase-3 in the mechanism of secondary injury of separated infarction in cerebellar cortex after middle cerebral artery occlusion in rats and it might give a new treatment strategy for individuals with human ischemic stroke.
