Comparing Human and Mouse Primary Submandibular Glands for Research Purposes

Objectives: Mouse submandibular glands (SMG) are similar in many ways to human salivary glands (e.g., anatomy, histology and physiology). However, there are some significant differences between the two organisms, and by extension, the SMG derived from them that must be taken into account for translational studies. The objective of this study is to detail similarities and differences between human and mouse SMG and offer practical guidelines for using both for research purposes.
Methods: To determine structural differences human and mouse SMG tissue sections were immunostained and subjected to confocal analysis using anti-ZO-1, anti-E-cadherin, anti-Aquaporin-5 (AQP5), and mouse anti-Cytokeratin-7 (CK7). To study their lifespan in cultures, fresh human and mouse SMG were homogenized using GentleMACS Tissue Dissociator, cells were isolated and plated on laminin-1 gel for 22 days.
Results: SMG tissue sections displayed apical ZO-1 and basolateral E-cadherin in both human and mouse. Moreover, SMG showed expression of apical AQP5 (marker for differentiated acinar cells) as well as basolateral CK7 (marker for ductal cells) in both species. A discernible difference is that human SMG show adjacent acinar and ductal cells, while structures in the mouse SMG appear to be either ductal or acinar. Cell culture studies revealed that human SMG cells develop distinct lumens with apical F-actin rings at 6-22 days while mouse SMG cells form cell clusters with apical F-actin ring at 6-14 days with over-expanding lumens with time in culture (at 22 days) indicative of loss of cell organization and presumably progressive cell death.
Conclusions: Despite the basic SMG interspecies similarities that make the mouse such an inviting option for research purposes, an abundance of anatomical, histological and physiological differences suggests the need for further investigation of these interspecial variations with a particular focus on describing their implications for applied salivary research.