Oral

Background
Vitamin D (VD) plays an important role in intestinal architecture and tight junction (TJ). In our previous study, we found the VD deficiency leads to irregular deformation of intestinal villi and intestinal bleeding, but the reason is not clear. Deformation of intestinal villi may be related to cytoskeleton remodeling and TJ dysfunction. In deeper aspect, cytoskeleton of the intestine is highly related to non-muscle myosin 2 (NM2). The lack of NM2 affects the appearance of cells and reduces TJ adhesion. Therefore, we hypothesized that VD deficiency would inhibit the performance of NM2, thereby causing intestinal villi deformation.

Aim
To understand whether VD-deficient mice will affect the performance of NM2 and the possible mechanism that may damage the gut integrity.

Methods
Male C57BL/6J mice were fed VDD (vitamin D deficient) diet or VDS (vitamin D supplement, 37.8 IU/per mouse) diet for 7 weeks. After sacrificed, TJ protein-1(TJP-1), E-cadherin (E-CAD), occludin, NM2A, NM2B, NM2C of ileum and colon tissues were studied by Weste blot. NM2A performance of jejunum and colon tissues were measured by immunofluorescence stain. 

Results
NM2 (especially NM2A and NM2C) expressions were significantly reduced in VDD group. We also found lower expressions of TJP-1 and E-CAD in ileum and colon tissues in VDD group. The surface linings of jejunal villi and colon for NM2A proteins staining were clear and sharp in the VDS group but blurry and irregular in the VDD group.

Discussion and Conclusion
Vitamin D plays a role in the expression of cytoskeleton protein. We successfully demonstrate that VDD could lead to worsened histologic damage with typically irregular edge lining of the jejunal mucosa. Further studies are needed to investigate the roles and clinical significance of various NM2 expressions.