Glutathione loaded solid lipid nanoparticles:preparation and in vitro evaluation as delivery systems of the antioxidant peptide to immunocompetent fish cells

BACKGROUND: Solid lipid nanoparticles (SLN) have not been used for peptide supply to fish cells. OBJECTIVE: To evaluate the potential of SLN to deliver the antioxidant glutathione (GSH) to the primary cultures of head-kidney (HK) leucocytes of Sparus aurata L. METHODS: SLN were produced using the amphiphilic lipid Gelucire® 50/13 according to the melt-emulsification method. In vitro stability and colorimetric studies for the antioxidant activity were carried out prior to biological assays on HK leucocytes. RESULTS: SLN sonicated in acidic medium were stable up to 3 months at 4◦C. A strong in vitro antioxidant activity effect for SLN was shown. The incubation of gilthead seabream HK leucocytes with GSH, GSSG or the sonicated and non-sonicated GSH-SLN(HAc) for 4 h had very few effects on HK cell activities. The phagocytic ability of HK leucocytes previously incubated with GSH was significantly increased in respect to the control cells. CONCLUSIONS: The technique of melt-emulsification provided particles with high association efficiency in GSH and even below 100 nm in size. However, no stimulant properties were observed after incubation of HK leucocytes with SLN and possible hypotheses explaining the observed findings are discussed.