Affordable Access

Neuronal injury after photoactivation of photofrin II.

Authors
Publication Date
Source
PMC
Keywords
  • Research Article
Disciplines
  • Medicine

Abstract

Photodynamic therapy has been used in the management of patients with malignant brain tumors even though the effects of this form of treatment on the adjacent normal brain are incompletely characterized. The authors examined, in sequential experiments, morphologic alterations affecting the cerebral cortex in rats injected with Photophrin II and exposed to light. Initially, minimal cell alterations, including cisternal swelling of both endoplasmic reticulum and Golgi apparatus, involved only neurons located in the superficial layers of the cerebral cortex exposed to light. These changes spread, over a period of several hours, from the surface to the bottom of the cortex and eventually involved the entire cortical segment exposed to light. The earliest structural signs of lethal injury to neurons developed over a period of 18 hours after porphyrins had been photoactivated and astrocytes had been severely damaged. Signs of lethal injury to neurons included an increase in the number of mitochondrial cristae and appearance of amorphous electron-dense deposits within swollen mitochondria. The appearance of these alterations was followed by segregation of intracytoplasmic organelles and fragmentation of nuclear and cytoplasmic membranes. The tissue changes, including those involving neurons, eventually progressed to coagulation necrosis at 48 hours. These observations suggest that prophyrins injected to rats (48 hours before photoactivation) cause swelling and necrosis of astrocytes. This is followed by neuronal necrosis, which appears at two time intervals; the initial neuronal necrosis occurs after the astrocytic disintegration. A second type of neuronal alteration appears after microvessels become thrombosed and ischemia is likely to develop.

There are no comments yet on this publication. Be the first to share your thoughts.

Statistics

Seen <100 times
0 Comments

More articles like this

Neuronal injury after photoactivation of photofrin...

on American Journal Of Pathology October 1992

Photoactivated Photofrin II: astrocytic swelling p...

on Journal of Neuropathology and... January 1992

The composition of Photofrin II

on Journal of Photochemistry and... Jan 01, 1990
More articles like this..