Changes of the chicken chorioallantoic membrane and the behaviour of transplanted glioblastoma

Glioblastoma is the most common brain malignancy and is marked by an extremely poor prognosis, despite advances in surgical and clinical neuro-oncology. Glioblastomas are very heterogenic in their biological and morphological features and they are widely investigated. Existing in vivo glioblastoma models are based on the inoculation of glioma cells or cell lines into the rodent brain, the dog brain or the use of transgenic mice causing spontaneous tumors. These models suffer from the variable growth rate and poor penetration, and are limited by the difficulty of obtaining morphological data. In our research we suggested the model in which the native human glioblastoma was transplanted into the chicken embryo chorioallantoic membrane. The glioblastoma was transplanted into the embryo's chorioallantoic membrane on the seventh–ninth day, when it was fully developed and could ensure the nutrition of the tumor. Transplantation was successful if the glioblastoma survived at least for 24 hours together with the embryo. The chorioallantoic membrane after transplantation showed thickening. Between 48 and 120 hours after transplantation the thickness of the membrane changed from 2x to 5x. Starting from 144 hours after transplantation the thickness of the membrane diminished. The tumor transplanted into the chorioallantoic membrane ingrows in it in the zones where the epithelium of the membrane was mechanically removed. The tumor keeps its proliferative activity until 48 hours of transplantation, afterwards the proliferative activity is noticed in the chorioallantoic membrane until 120 hours of transplantation. This shows that the main processes take place in the zone where the tumor adheres to the chorioallantoic membrane. The human glioblastoma transplanted on chicken chorioallantoic membrane repeated all the essential stages of tumor growth, which are also typical of other mammal models. This model reflects the morphological and biological features of the glioblastoma, allows to evaluate the invasivity, the progress of the tumor, and to investigate new medicines.