Dextran sulfate sodium-induced colitis generates a transient thymic involution--impact on thymocyte subsets.

Area of Science:

• Immunology
• Gastroenterology
• Animal Models

Background:

• Dextran sulfate sodium (DSS)-induced colitis is a common model for inflammatory bowel disease (IBD).
• Previous work showed differing disease chronicity in C57Bl/6J and BALB/cJ mice after DSS administration.
• The impact of DSS-induced colitis on the thymus requires further investigation.

Purpose of the Study:

• To investigate the effects of DSS-induced colitis on thymic cellularity and thymocyte maturation in C57Bl/6J and BALB/cJ mice.
• To correlate thymic changes with the severity and phase of intestinal inflammation.

Main Methods:

• Induction of colitis using DSS in C57Bl/6J and BALB/cJ mice.
• Flow cytometry analysis of thymocyte populations (DN, DP, SP) at different time points post-DSS.
• Assessment of thymic size and total thymocyte numbers.

Main Results:

• C57Bl/6J mice experienced a significant decrease in thymic size and total thymocytes during acute inflammation, with enrichment of mature SP thymocytes and reduced DP thymocytes. Thymic parameters normalized as inflammation resolved.
• BALB/cJ mice showed milder thymic alterations, but an increase in CD44(+)CD25(-) (DN1) thymocytes and a decrease in CD44(-)CD25(-) (DN4) thymocytes correlated with colitis severity.
• Thymic recovery was observed in C57Bl/6J mice during the chronic phase of inflammation.

Conclusions:

• DSS-induced colitis causes distinct acute thymic alterations in C57Bl/6J mice that are reversible.
• Specific thymocyte subsets (DN1, DN4) are altered in BALB/cJ mice in relation to colitis severity.
• Thymic changes are closely associated with the intestinal inflammatory response in colitis models, irrespective of the specific inflammatory trigger.