Modification of Perivascular Subcutaneous Connective Tissue Reaction following X-ray Irradiation by Several Vasoconstricting Agents

The rabbits subcutaneous connective tissue reaction following X-ray irradiation and inhibitary effects of several vasoconstricting agents against this reaction were studied by means of supravital staining of the stretch preparation of the subcutaneous connective tissue. In irradiated connective tissue perivascular granulocytic emigration was observed at the beginning of the process. They increased in number till 8-12 hours, and then degenerated and were devoured by monocytes or histiocytes disappearing in 1-3 days. In addition the monocytes increased in number in 1-3 days. This tissue reaction was inhibited for 3 postirradiation hours, when the epinephrine, norepinephrine, phenylephrine, naphazoline or atropin were administered locally 5 minutes before or immediately after irradiation. Following non-local administration of the phenylephrine or naphazoline 5 minutes before or immediately after irradiation the tissue reaction was inhibited for 5 postirradiation hours. The post-irradiation treatment by phenylephrine produced less inhibitary effect as compared with pre-irradiation treatment. As the mechanisms of this inhibitary action the antagonism to the radiation induced vasodilatation and the hypoxia caused by vasoconstriction were discussed.