Gastrointestinal radiation injury: Prevention and treatment

Table 1 Examples of putative intestinal radioprotectants tested in pre-clinical studies

Biological agent	Suggested effect/mechanism	Suggested radioprotection
Glutamine, arginine enriched diet[103]	Enhanced mucosal healing	Protective effect on rat intestine compared to control
Vitamin- E[104]	Reduction of oxidative stress	Protective effect on rat intestine compared to control
Captopril[105]	Inhibition of pro-inflammatory enzyme angiotensin-1-converting enzyme	Protective effect on mouse intestine compared to control
Rofecoxib[106]	Selective Inhibition of cyclooxygenases -2 enzyme	Protective effect on rat intestine compared to control
Clopidogrel[107]	Inhibition of platelets aggregation with reduced vascular sclerosis	Protective effect on rat intestine
Thalidomide[108]	Protection to microvascular bed	Attenuated injury to rat endothelial cells of micro vascular bed compared to control
Simvastatin[109]	Attenuate endothelial cell injury	Attenuated delayed intestinal injury in rats
Glucagon-like peptide-2 (GLP-2)[110]	Increased mucosal mass	Intestinal trophic and protective effect to rat intestine
Octreotide[111,112]	Modulation the inflammatory effects mediated by over expression of NFκB	Ameliorated inflammation and injury in rat intestine
Prostaglandin E-2[113]	Pro-proliferative and anti-apoptotic effect on intestinal epithelium	Increased crypts survival
Anti-Transforming growth factors beta receptor[114]	Biological inhibition of extracellular remodeling	Reduced intestinal injury and fibrosis compared to IgG treated control mice
Toll like receptor 5 agonist derived from Salmonella flagellin[115]	Activation of intestinal immune response via NFκB signalling pathway	Protective effect to mice intestine
Intestinal sterilisation[116] Germ-free raised mice	Reduced number of translocated bacteria, sepsis and inflammation	Reduced intestinal cell apoptosis
Probiotic bacteria[117] (Lactobacillus species)	Restored intestinal microbiota imbalance	Reduces intestinal damage, sepsis and death in rodents