Evaluation of sodium alginate for encapsulation-vitrification of testicular Leydig cells

This study reports encapsulation-vitrification of Leydig cells. The Leydig cells were encapsulated in sodium alginate beads of different sizes and cryopreserved by vitrification or slow freezing. Physico-chemical characterization of beads was done by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Fluorescence Recovery after Photobleaching (FRAP) and in vitro biodegradation study. Surface morphology of cryopreserved cell-encapsulated beads was evaluated by Environmental Scanning Electron Microscopy (E-SEM), encapsulation efficiency and viability of cells were assessed by Trypan blue assay, mitochondrial activity (MTT assay) and cytoplasmic esterase enzyme activity (FDA assay), respectively. Results showed that vitrification gives better results than slow freezing with respect to surface morphology as well as cell viability of the cell-encapsulated beads (86.94 ± 2.20% vs. 67.94 ± 2.30%; p < 0.05). Encapsulation of cells in small diameter beads (1.8 mm) gave a better cell proliferation rate than large (2.1 mm and 2.7 mm). There was a significant difference in the population doubling time (47.9 ± 1.7 h vs. 67.1 ± 2.5 h) and cell proliferation rate (0.50 ± 0.24 vs. 0.36 ± 0.24 per day) of vitrified-warmed cell encapsulated beads with different diameter (p < 0.05). Encapsualtion in sodium alginate beads is a promising method for cryopreservation of Leydig cells by slow freezing as well as vitrification.