Abstract
Tumor blood vessels (TBV) play an important role in the growth of tumors and in cancer therapy.There has been much literature on the vasculature of TBV, but little work on TBV in the human oral region.So the purpose of this study was to clarify the ultrastructure of TBV in human oral squamous cell carcinoma.Conclusions are drawn as follows:
I.Normal blood vessels in oral mucous membrane partially showed endothelial fenestrations with diaphragm (F. D.), but endothelium without F. D.was dominant.The numerical ratio of the former to the latter was about one to four.On the other hand only endothelium without F. D.existed in the blood vessels of tongue muscle.
2.In TBV in the untreated cases there were some morphological characteristics.
1) The ratio of the number of endothelium with F. D.to ones without F. D.increased twofold, and discontinuous endothelium (gap) appeared.The gap and F. D.always showed coexistence in the same vessels.
2) Irregular surface, especially numerous luminal processes, characterized the configuration of endothelial cells.
3) Markedly elongated tortuous and dilated junctions were frequent.
4) Two special cell components were observed: Weibel-Palade granules and tubuloreticular inclusions.
The above-described findings, seen mainly in TBV with a diameter of about 20μ, suggested that the permeability of TBV increased considerably.
3.On the other hand, tumor capillaries with a diameter of less than about 8μin the untreated cases were composed of plump endothelial cells with low electric density due to sparcity of cell organelles.A number of mesenchymal cells, which surrounded these capillaries, may be related to angiogenesis.
4.After exposure to X-ray with combinations of bleomycin TBV changed ultrastructurally.
In the earlier period, lysosomes and microfilaments in the cytoplasm of the endothelium and irregularity of the nucleus appeared.During the period in which the treatment was completed, the number of lysosomes and microfilaments increased frequently.Furthermore, thrombosis, necrosis of endothelium and destruction of vessels was observed. Namely exposure to X-ray with combinations of bleomycin was presumed to have damaged the endothelium of TBV.
