Lymphatic dysfunction has been linked to inflammation since the 1930’s. Lymphatic function in the gut and mesentery is grossly underexplored in models of IBD despite the use of lymphatic occlusion in early models of IBD. Activation of the innate and adaptive immune system is a hallmark of TNBS-induced inflammation and is linked to disruption of the intrinsic lymph pump. Recent identification of crosstalk between lymphatic vessel resident immune cells and regulation of lymphatic vessel contractility underscore the importance of the timing of lymphatic dysfunction during tissue inflammation in response to TNBS.

To evaluate lymphatic function in TNBS induced inflammation, lymph was collected and flow measured from mesenteric lymphatics. Cellularity and cytokine profile of the lymph was also measured. Histopathology was performed to determine severity of injury and immunofluorescent staining of the mesentery was done to evaluate changes in the population of immune cells that reside near and on gastro-intestinal collecting lymphatics.

Lymph transport fell 24hrs after TNBS administration and began recovering at 72hrs. Significant reduction of lymph flow preceded significant increase in histopathological score and occurred simultaneously with increased MPO activity. These changes were preceded by increased MHCII⁺ cells surrounding mesenteric lymphatics leading to an altered lymphatic environment that would favor dysfunction.

Alterations in environmental factors that effect lymphatic function occur before the development of gross GI inflammation. Reduced lymphatic function in TNBS-mediated inflammation is likely an early factor in the development of injury and that recovery of function is associated with resolution of inflammation.