Histopathological assessment of protective effects of N-acetyl cysteine on rat lung exposed to ionizing radiation

: Aim: Radiotherapy (RT) has been used for many years as a curative or adjuvant with chemotherapy and surgery in the treatment of various thoracic malignancies. However, adverse pulmonary effects such as pneumonia and fibrosis can be life-threatening. For this reason, it is very prominent to support RT with compounds that will reduce side effects. This study examines the protective effect of N-acetyl cysteine (NAC), an anti-inflammatory and an antioxidant, against lung damage caused by radiotherapy. Materials and Methods: Twenty-eight female Wistar albino rats were used. The rats were divided into four groups control (injected with saline), NAC (injected with NAC), RT (exposed to radiation) RT+NAC (injected with NAC+exposed to radiation). After three months of irradiation, rats were sacrificed and lung samples were taken for light and electron microscopic evaluation. The alveolar wall thickness, mast cell count, and hyaline membrane formation were evaluated with light microscopy. Electron microscopy was used to evaluate morphological changes in the lungs. Results: The results showed a significant increase in scores of alveolar wall thickness and hyaline membrane formation and mast cell count in the RT rats. In the RT+NAC group, administration of NAC to rats caused significant amelioration in the measured parameters. Similarly, in electron microscopic examination, it was observed that the morphological damages in the RT group were significantly reduced in the RT+NAC group. Conclusion: The results obtained in this study suggested that the use of NAC before thoracic radiotherapy may reduce the damage to the lungs due to radiotherapy.