Interaction of Hypericin Embedded in Liposomes with the Ocular Tissue of New Zealand Rabbits for Application in Photodynamic Therapy

Abstract

The potent photodynamic properties of hypericin (HY) elicit a range of light-dependant virucidal and tumoricidal activities. This work highlights the interaction of liposomes loaded with HY with the aqueous humor and crystalline lens of the rabbits’ eye in comparison with those treated with HY only. Six groups of New Zealand rabbits of six rabbits each were used in this study. The rabbits received 30 µl of HY or liposomes loaded with hypericin topically once a day for one week as an eye drop of HY concentration 1–9µM.The eyes of rabbits were exposed to He-Ne laser for 5 minutes after 30 minutes from administration of HY or liposomes loaded with HY for the studied groups. Total soluble protein, molecular weight distribution, electrophoretic mobility and refractive index for both aqueous humor and soluble lens crystallins were investigated for the studied samples. The obtained results showed an increase in the solubility of lens protein and aqueous humor, an increase in the molecular weights of s and gamma proteins accompanied by fluctuations in the electrophoretic mobility and slight decrease in the refractive index at high concentration of HY. The changes were higher in the samples treated with HY more than those treated with liposomes loaded with HY. It is concluded from the obtained data that hypericin embedded in liposomes may be used as a photosensitizer for photodynamic therapy at low fractionated doses with minimal side effects.