Isolation and primary culture of rat thymic epithelial cells using actinidin enzyme of kiwi fruit

Proteolytic enzymes specially collagenase are used for degredation of extracellular matrix, cell isolation and primary cell culture. It is important to substitute a low cost and easily obtained plant or animal protease for collagenase. In the present study the enzyme actinidin which is found abundantly in kiwi fruit, was used to isolate thymic epithelial cells from rat thymus. Actinidin with different concentrations (from 1 to 10 mg/ml) and at different times (3, 4 or 5h) was used to isolat rat thymic epithelial cells. The isolated epithelial cells were cultured on collagen coated dishes in willam's E medium. The percentage of viable isolated cells was estimated by the trypan blue test and morphology of the cells examined microscopically after staining with Papanicoloau. Actinidin with a concentration of 4 mg/ml for 3.5-4 h digested extra-cellular matrix of rat thymus and isolated thymic epithelial cell appropriately. The rate of viability of the separated cells was estimated 90-95% in all isolates. The results of this study indicated actinidin is comparable to collagenase in isolation of epithelial cells from the thymus of rat and probably other animals. Considering its simpler purification and its low cost, this enzyme is a suitable and safe substitute for collagenase which can be used for isolation of thymic epithelial cells from rat and probably other animals.