Curcumin/pharmacology; Endothelial Cells/drug effects; Intracellular Signaling Peptides and Proteins/metabolism; NF-kappa B/metabolism; Protein Serine-Threonine Kinases/metabolism; Proto-Oncogene Proteins c-akt/metabolism; Radiation-Sensitizing Agents/pharmacology; Abnormalities, Radiation-Induced/drug therapy; Animals; Caspase 3/genetics; Caspase 3/metabolism; Cell Death/drug effects; Cell Death/radiation effects; Cell Survival/drug effects; Cell Survival/radiation effects; Dose-Response Relationship, Drug; Endothelial Cells/radiation effects; Forkhead Box Protein O1; Forkhead Transcription Factors/genetics; Forkhead Transcription Factors/metabolism; Gene Expression Regulation; Gene Silencing; Humans; Intestines/blood supply; Intestines/drug effects; Intestines/radiation effects; Intracellular Signaling Peptides and Proteins/genetics; Male; Microvessels/cytology; NF-kappa B/genetics; Phosphatidylinositol 3-Kinases/genetics; Phosphatidylinositol 3-Kinases/metabolism; Protein Serine-Threonine Kinases/genetics; Proto-Oncogene Proteins c-akt/genetics; Proto-Oncogene Proteins c-mdm2/genetics; Proto-Oncogene Proteins c-mdm2/metabolism; RNA, Small Interfering; Rats; Rats, Sprague-Dawley; TOR Serine-Threonine Kinases