OBJECTIVE: To construct the recombinant adeno-associated virus(rAAV) vector plasmid pSNAV2.0-TK containing HSV1-TK gene, to produce recombinant adeno-associated virus rAAV2/HSV1-TK, and to detect the integration and expression of HSV1-TK gene in lens epithelial cells transfected by rAAV2/HSV1-TK, and to provide foundation for gene therapy of posterior capsular opacification. METHODS: The recombinant vector plasmid constructed by gene recombinant technology was analyzed by PCR and restriction enzyme digestion. The cell strain BHK-21/TK was screened by G418 after the plasmid was transfected into BHK-21 cells,with the helper virus HSV1-rc/UL2 to produce the recombinant virus rAAV2/HSV1-TK. The purity of rAAV2/HSV1-TK was detected by SDS-PAGE and HPLC, and the titre of rAAV2/HSV1-TK was observed by dot blot hybridization. The HSV1-TK gene in lens epithelial cells transfected by rAAV2/HSV-TK was investigated by PCR and RT-PCR. RESULTS: The recombinant plasmid proved successful by PCR and restriction enzyme digestion. The recombinant virus rAAV2/HSV1-TK was produced successfully and its titre was 1 x 10(12) v.g./mL by dot blot hybridization. The HSV1-TK gene was integrated and expressed in lens epithelial cells. CONCLUSION The recombinant adeno-associated virus vector plasmid containing HSV1-TK gene is successfully constructed, and high titre recombinant adeno-associated virus (rAAV2/HSV1-TK) is obtained. The HSV1-TK gene in lens epithelial cells is expressed after being transfected by rAAV2/HSV1-TK.
Animals ; Cloning, Molecular ; Cricetinae ; Dependovirus ; genetics ; metabolism ; Epithelium, Corneal ; cytology ; metabolism ; Genetic Vectors ; Herpesvirus 1, Human ; enzymology ; genetics ; Rabbits ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Thymidine Kinase ; biosynthesis ; genetics ; Transfection

The role of nitric oxide (NO) in the ocular surface remains unknown. We investigated the conditions leading to an increase of NO generation in tear and the main sources of NO in ocular surface tissue. We evaluated the dual action (cell survival or cell death) of NO depending on its amount. We measured the concentration of nitrite plus nitrate in the tears of ocular surface diseases and examined the main source of nitric oxide synthase (NOS). When cultured human corneal fibroblast were treated with NO producing donor with or without serum, the viabilities of cells was studied. We found that the main sources of NO in ocular surface tissue were corneal epithelium, fibroblast, endothelium, and inflammatory cells. Three forms of NOS (eNOS, bNOS, and iNOS) were expressed in experimentally induced inflammation. In the fibroblast culture system, the NO donor (SNAP, S-nitroso-N-acetyl-D, L-penicillamine) prevented the death of corneal fibroblast cells caused by serum deprivation in a dose dependent manner up to 500 micrometer SNAP, but a higher dose decreased cell viability. This study suggested that NO might act as a doubleedged sword in ocular surface diseases depending on the degree of inflammation related with NO concentration.
Animals ; Apoptosis/drug effects/physiology ; Aqueous Humor/metabolism ; Blood Proteins/pharmacology ; Cell Survival/drug effects/physiology ; Cells, Cultured ; Epithelium, Corneal/*cytology/*enzymology ; Fibroblasts/cytology/enzymology ; Humans ; Nitric Oxide/biosynthesis/*physiology ; Nitric Oxide Donors/pharmacology ; Nitric Oxide Synthase/metabolism ; Nitric Oxide Synthase Type I ; Nitric Oxide Synthase Type II ; Nitric Oxide Synthase Type III ; Penicillamine/*analogs & derivatives/pharmacology ; Peroxynitrous Acid/biosynthesis ; Rabbits ; Tears/metabolism ; Uveitis/metabolism