| Microvessel density in tumor is correlated with histologic grading and prognosis, while tumor angiogenesis is an important indicator for evaluating therapeutic effect and prognosis. Therefore angiogenesis investigation now becomes a new field in the prevention and therapy of tumors. Accordingly, to monitor tumor angiogenesis in vivo is a challenge to imaging medicine. At present, more attention is paid to MR PWI which can study distribution of microvessel and blood perfusion of tissue. Consequently, hemodynamics information is obtained by this way. However, there was little animal experimental study on imaging tumor angiogenesis. Certainly, to establish a technological platform for evaluating tumor angiogenesis in vivo, such as animal model of brain glioma, the most common tumor in central nervous system, will promote the basic research of imaging medicine and other clinical medicine. The purpose of this study is to establish a rat C6 brain glioma model, to investigate its feasibility in imaging medicine research, especially in MR PWI research, and to initially study MR PWI technique of the model.Materials and methodsIn part one of the study, 16 rats were divided into 2 groups randomly, each group contained 8 rats. C6 cells were inoculated into the right caudate nucleus of the rats by stereotactic procedure. 1.0 X106 C6 cells were inoculated in group one, while 1.5 X 106 C6 cells in group two. On the following days, common condition, body weight, surviving time and MR features of the rats were observed. The maximum diameter of tumor was measured, and volume was calculated. Tumor age was recorded when the maximum diameter reached 3mm, and time window, the time from such tumor age to the death of rat, was counted. The specimens of tumors for pathological study were collected in the dying time or after the death of rats immediately.In part two of the study, 15 rats with C6 brain glioma were divided into 3 groups randomly, each group contained 5 rats, then MR PWI scanning was performed. The dosage of contrast medium was 0.2mmol'kg-1 in group one, 0.4mmol kg-1 in group two and 0.6mmolkg~' in group three. According to time-signal curve of PWI, rCBV, SRRmax, QrCBv and QsRRmax were computed. The rCBV and SRRmax of normal brain were compared to those of tumor, and the QK;BV and QsRRmax of rats of 3 groups were analyzed.In data analysis, SPSS 10.0 statistical package was employed to perform test of normality, ANOVA, and t test, et al.ResultsIn part one of the study, C6 brain glioma was developed in all of the rats. The immunohistochemistry examination of tumor tissue showed the expression of GFAP and S-100 proteins. There was no implantation under scalp and no metastasis in lungand liver, however, ascites was found in one rat. In earlier period, the rats manifestated as psychiatric depression, the power of attack weakened , and the activity decreased. In later period, the weight-loss of rats was obvious, while the symptoms includs hemiplegia, hemorrhage around orbits, epilepsy, dyscrasia, et al. On MR imaging, the tumors appeared as long TI , long Ta signal and annular enhancement with round shape or the similar. The surviving time of rats were 23.50 ± 3.93 d in group one, longer than 17.75 ± 2.38 d in group two (P<0.01). With increasing of tumor age, the maximum diameter of tumor enlarged in a linear manner. The maximum diameter in the dying time was 9.19 ± 2.36mm (group one) and 9.19±0.96mm (group two), there was no significant difference between the two groups (P>0.05), however, the homogeneity of maxmium diameters is better in group two than in group one. The volume of tumor enlarged in an exponential manner. The volume in the dying time was 515.66 ± 303.33mm3 (group one) and 504.91 ±176.49mm3 (group two), there was no significant difference between the two groups (P>0.05). The tumor age was 11.50 ± 0.93 d (group one) and 8.88 ± 1.25 d (group two) as tumor maximum diameter reached 3mm, the age in group one was older than that in group two (P<0.01). The time window to be used for obse...
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