The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport

Natalie L. Trevaskis; Luojuan Hu; Suzanne M. Caliph; Sifei Han; Christopher J.H. Porter

doi:10.3791/52389

Method Article

The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport

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DOI:

10.3791/52389

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March 6th, 2015

Natalie L. Trevaskis¹ , Luojuan Hu¹ , Suzanne M. Caliph¹ , Sifei Han¹ , Christopher J.H. Porter¹

¹Drug Delivery, Disposition, and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus)

Summary

Here we describe a technique to cannulate the mesenteric lymph duct in rats which enables quantification of lipid and drug transport via the lymphatic system following intestinal delivery. The technique can be adapted to assess mesenteric lymph concentrations and/or transport of fluid, immune cells, peptides, proteins and lipophilic molecules.

Abstract

The intestinal lymphatic system plays key roles in fluid transport, lipid absorption and immune function. Lymph flows directly from the small intestine via a series of lymphatic vessels and nodes that converge at the superior mesenteric lymph duct. Cannulation of the mesenteric lymph duct thus enables the collection of mesenteric lymph flowing from the intestine. Mesenteric lymph consists of a cellular fraction of immune cells (99% lymphocytes), aqueous fraction (fluid, peptides and proteins such as cytokines and gut hormones) and lipoprotein fraction (lipids, lipophilic molecules and apo-proteins). The mesenteric lymph duct cannulation model can therefore be used to measure the concentration and rate of transport of a range of factors from the intestine via the lymphatic system. Changes to these factors in response to different challenges (e.g., diets, antigens, drugs) and in disease (e.g., inflammatory bowel disease, HIV, diabetes) can also be determined. An area of expanding interest is the role of lymphatic transport in the absorption of orally administered lipophilic drugs and prodrugs that associate with intestinal lipid absorption pathways. Here we describe, in detail, a mesenteric lymph duct cannulated rat model which enables evaluation of the rate and extent of lipid and drug transport via the lymphatic system for several hours following intestinal delivery. The method is easily adaptable to the measurement of other parameters in lymph. We provide detailed descriptions of the difficulties that may be encountered when establishing this complex surgical method, as well as representative data from failed and successful experiments to provide instruction on how to confirm experimental success and interpret the data obtained.

Introduction

Lymph flows from the small intestine via a unidirectional process that originates at single lacteals that are contained within each small intestinal villi¹. Lacteals are relatively permeable to fluid, macromolecules and cells and lymph formation thus commences with the entry of these factors into lacteals. The initial lymph in the lacteals subsequently flows from the intestine via a network of lymphatic microvessels, collecting (afferent) lymphatic vessels, a series of mesenteric lymph nodes and ultimately the post-nodal (efferent) lymph vessels. Within the nodes, lymph passes through a series of medullary sinuses where exchange occurs with node resident im....