Local radiotherapy of exposed murine small bowel: Apoptosis and inflammation

Andrea Polistena¹^,4 , Louis Banka Johnson¹ , Salomé Ohiami-Masseron¹ , Lena Wittgren² , Sven Bäck² , Charlotte Thornberg² , Virgil Gadaleanu³ , Diya Adawi¹ and Bengt Jeppsson¹

¹Department of Surgery, Malmö University Hospital, Lund University, Malmö, Sweden

²Department of Radiation Physics Malmö University Hospital, Lund University, Malmö, Sweden

³Department of Pathology, Malmö University Hospital, Lund University, Malmö, Sweden

⁴I Scuola di Specializzazione in Chirurgia Generale, Dipartimento "Pietro Valdoni", Università degli Studi di Roma "La Sapienza", Rome, Italy

author email corresponding author email

BMC Surgery 2008, 8:1doi:10.1186/1471-2482-8-1


Published:	3 January 2008

Abstract

Background

Preoperative radiotherapy of the pelvic abdomen presents with complications mostly affecting the small bowel. The aim of this study was to define the features of early radiation-induced injury on small bowel.

Methods

54 mice were divided into two groups (36 irradiated and 18 sham irradiated). Animals were placed on a special frame and (in the radiated group) the exteriorized segment of ileum was subjected to a single absorbed dose of 19 or 38 Gy radiation using 6 MV high energy photons. Specimens were collected for histology, immunohistochemistry (IHC) and ELISA analysis after 2, 24 and 48 hours. Venous blood was collected for systemic leucocyte count in a Burker chamber.

Results

Histology demonstrated progressive infiltration of inflammatory cells with cryptitis and increased apoptosis. MIP-2 (macrophage inflammatory protein) concentration was significantly increased in irradiated animals up to 48 hours. No significant differences were observed in IL-10 (interleukin) and TNF-α (tumour necrosis factor) levels. IHC with CD45 showed a significant increase at 2 hours of infiltrating leucocytes and lymphocytes after irradiation followed by progressive decrease with time. Caspase-3 expression increased significantly in a dose dependent trend in both irradiated groups up to 48 hours.

Conclusion

Acute small bowel injury caused by local irradiation is characterised by increased apoptosis of crypt epithelial cells and by lymphocyte infiltration of the underlying tissue. The severity of histological changes tends to be dose dependent and may affect the course of tissue damage.