Proctitis

The direct effect of ionizing radiation during radiation therapy damages the DNA, lipids, and proteins of cells (both cancerous and non-cancerous) in the GI tract. In the rodent models, proctitis is induced with either a single bolus of acute radiation, or 8 fractionated, smaller doses, directed at approximately the most distal 2 cm of the colon (a lead shield protects the remainder of the animal’s body). Animals are monitored daily and evaluated for overall health and survival in addition to diarrhea and bloody stool incidence. A major readout in the model is proctitis severity determined via longitudinal video endoscopic assessments over the course of the study. Peak disease differs based on the method of induction, with disease persisting through the final evaluation which typically includes histopathology.

• Advantages: short model duration, consistent disease incidence, direct model of clinical disease induction.
• Disadvantages: smaller market than IBD.

• Sprague Dawley Rat, Lewis Rat
• C57Bl/6 Mice

• Percent weight change
• Survival
• Diarrhea and bloody stool Incidence
• Endoscopy: proctitis scoring
• Terminal colon weight and length measurement
• Terminal histopathology and/or IHC analyses

• Tissue localized protein analyses
• Peripheral lymphoid organ immunophenotyping
• Intestinal lamina propria immunophenotyping
• Custom assays