Histological changes in the normal rat brain after gamma irradiation

Area of Science:

• Neuroscience
• Radiation Oncology
• Histopathology

Background:

• Gamma Knife radiosurgery is used for treating brain tumors and arteriovenous malformations.
• Understanding the effects of radiation on normal brain tissue is crucial for optimizing treatment and minimizing side effects.

Purpose of the Study:

• To investigate the time- and dose-dependent effects of Gamma Knife irradiation on the parietal cortex of Wistar rats.
• To characterize the cellular and vascular changes induced by different radiation dosages.

Main Methods:

• Wistar rats were subjected to Gamma Knife irradiation at dosages of 50, 75, and 120 Gy.
• Histochemical, immunocytochemical, and videomicroscopy analyses were performed on brain tissue at various time points.
• Assessment included astrocyte morphology, vascular changes (vasodilation, fibrin deposition, thickening), Evans Blue leakage, necrosis, and swelling.

Main Results:

• 50 Gy: Astrocytic changes at 3 months, vasodilation and fibrin at 12 months; no leakage or necrosis.
• 75 Gy: Astrocytic changes at 1 month, vascular changes at 3 months, leakage and necrosis at 4 months, with arteriolar occlusion and swelling.
• 120 Gy: Rapid astrocytic changes (3 days), leakage (3 weeks), marked vasodilation, rarefaction, and necrosis (4 weeks); no significant swelling.

Conclusions:

• Gamma Knife irradiation induces distinct time- and dose-dependent pathological changes in normal brain tissue.
• The observed effects range from subtle astrocytic alterations to severe vascular damage and necrosis.
• Findings provide a foundation for assessing radiosurgery impact on critical brain regions and inform future treatment strategies.