Background and Objectives:�Stem cells are characterized by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specific cell types. Wharton's jelly is the appropriate source of mesenchymal stem cells (MSCs) that have high differentiation competence. The aim of this study was differentiation of MSCs to lens fiber cells. In differentiation pathway of lens fiber cells, crystallins are expressed . Thus, crystallins can be used as differentiation marker of lens fiber cells.

  Method: In the current study MSCs were isolated from the mouse umbilical cord. It was minced into 1-2 mm³ fragments and then were incubated with collagenase type IA following pipetting for mechanical isolation of cells. Cell suspension was plated in 25 cm² culture flasks. Alkaline Phosphatase detection kit was used for staining of undifferentiated UC-MSCs from passage I. In the experimental group MSCs were plated in the maintenance medium supplemented with bovine vitreous body (1:3 v/v) for induction. Protein lysate were prepared from cells on days 10 of induction and were analyzed on polyacrylamide gels and transferred to nitrocellulose membranes. Rat lens extract was used as a positive control. Anti-alpha A, alpha B crystallin, secondary antibody, vectastain ABC- kit (standard) and vector blue alkaline phosphatase substrate kit III were used.

  Results: Mouse umbilical cord MSCs had alkaline phosphatase activity. Morphological studies and separation of proteins in electrophoresis indicated that experimental group cells might probably differentiated into lens fiber cells.

  Conclusion: Mouse umbilical cord could be used as an appropriate source for MSCs. MSCs had fibroblast- like morph and experimental group indicated the presence of fiber-like cells that were long, thin, and parallel aligned. Electrophoresis and Western blot analysis showed there was a detectable expression of early developmental marker of lens fiber cells differentiation in experimental group.