title: Selective gene transfer to the retina using intravitreal ultrasound irradiation.
abstract: This paper aims to evaluate the efficacy of intravitreal ultrasound (US) irradiation for green fluorescent protein (GFP) plasmid transfer into the rabbit retina using a miniature US transducer. Intravitreal US irradiation was performed by a slight modification of the transconjunctival sutureless vitrectomy system utilizing a small probe. After vitrectomy, the US probe was inserted through a scleral incision. A mixture of GFP plasmid (50 μL) and bubble liposomes (BLs; 50 μL) was injected into the vitreous cavity, and US was generated to the retina using a SonoPore 4000. The control group was not exposed to US. After 72 h, the gene-transfer efficiency was quantified by counting the number of GFP-positive cells. The retinas that received plasmid, BL, and US showed a significant increase in the number (average ± SEM) of GFP-positive cells (32 ± 4.9; n = 7; P < 0.01 ). No GFP-positive cells were observed in the control eyes (n = 7). Intravitreal retinal US irradiation can transfer the GFP plasmid into the retina without causing any apparent damage. This procedure could be used to transfer genes and drugs directly to the retina and therefore has potential therapeutic value.
authors.affiliation: Department of Ophthalmology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8520, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Sonoda
authors.forename: Katsuro
authors.initials: K
authors.lastname: Tachibana
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Makoto
authors.initials: M
authors.lastname: Shirasawa
authors.forename: Hiroto
authors.initials: H
authors.lastname: Terasaki
authors.forename: Eisuke
authors.initials: E
authors.lastname: Uchino
authors.forename: Ryo
authors.initials: R
authors.lastname: Suzuki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Maruyama
authors.forename: Taiji
authors.initials: T
authors.lastname: Sakamoto