Abstract
Purpose: :
Side population cells (SP cells) have been identified and characterized in various tissues since SP cells derived from bone marrow was reported to be enriched for stem cell activity. We also have identified SP cells in lacrimal and salivary glands and examined their functions. As a result, it was shown that SP cells in both glands had the potential to restore the damaged function through the mediation of their soluble factors, including clusterin, without stem cell activity such as cell reconstitution (ARVO 2007).
Methods: :
In this study, to examine whether clusterin is involved in recovery of secretory function, recombinant lentivirus expressing clusterin (Lenti-Clu) or green fluorescent protein (GFP, Lenti-GFP) were directly injected into mouse submandibular glands of which hypofunction was induced by irradiation. At day 7 following injection of viruses, the transduction efficiency was analyzed.
Results: :
Tissue sections of submandibular glands were immunostained for GFP and its positive signals were detected in about 16% of cells in the glands. In addition, the secretory ability of the glands was confirmed after pilocarpine stimulation 4, 8 and 16 weeks after injection of viruses. Saliva secretion was restored in the Lenti-Clu-injected mice as compared with the Lenti-GFP-injected mice.
Conclusions: :
These results suggest that clusterin is involved in recovery of secretory function in damaged glands. We provide evidence suggesting the possibility of clinical application of SP cell-related factor, clusterin, to treat exocrine dysfunction and possibly the age-related dry eye disorders.
Keywords: gene transfer/gene therapy • lacrimal gland • antioxidants