Influence of heme oxygenase-1 gene transfer on the viability and function of rat islets in in vitro culture

AIM. To investigate the influence of heme oxygenase-1 （HO-1） gene transfer on the viability and function of cultured rat islets in vitro. METHODS： Islets were isolated from the pancreata of Sprague-Dawley rats by intraductal collagenase digestion, and purified by discontinuous Ficoll density gradient centrifugation. Purified rat islets were transfected with adenoviral vectors containing human HO-1 gene （Ad- HO-1） or enhanced green fluorescent protein gene （Ad- EGFP）, and then cultured for seven days. Transfection was confirmed by fluorescence microscopy and Western blot. Islet viability was evaluated by acridine orange/ propidium iodide fluorescent staining. Glucose-stimulated insulin release was detected using insulin radioimmunoassay kits and was used to assess the function of islets. Stimulation index （SI） was calculated by dividing the insulin release upon high glucose stimulation by the insulin release upon low glucose stimulation. RESULTS： After seven days culture, the viability of cultured rat islets decreased significantly （92% ± 6% vs 52% ± 13%, P 〈 0.05）, and glucose-stimulated insulin release also decreased significantly （6.47 ± 0.55 mIU/ L/30IEO vs 4.57 ± 0.40 mIU/L/3OIEO., 14.93 ± 1.17 mIU/L/30IEQ vs 9.63 ± 0.71 mIU/L/30IEQ, P 〈 0.05）. Transfection of rat islets with adenoviral vectors at an 1±10 of 20 was efficient, and did not impair islet function. At 7 d post-transfection, the viability of Ad-HO-1 transfected islets was higher than that of control islets（71% ± 15% vs 52% ± 13%, P 〈 0.05）. There was no significant difference in insulin release upon low glucose stimulation （2.8 mmol/L） among Ad-HO-1 transfected group, Ad-EGFP transfected group, and control group （P 〉 0.05）, while when stimulated by high glucose （16.7 mmol/L） solution, insulin release in Ad-HO-1 transfected group was significantly higher than that in Ad-EGFP transfected group and control group, respectively （12.50 ±2.17 mIU/L/30IEQ vs 8.87 ± 0.65 mIU/L/30IEQ, 12.50 ± 2.17 mIU/L/30IEQ vs 9.63 ± 0.71 mIU/L/30IEQ, P 〈 0.05）. The SI of Ad-HO-1 transfected group was also significantly higher than that of Ad-EGFP transfected group and control group, respectively （2.21 ± 0.02 vs 2.08 ± 0.05; 2.21 ± 0.02 vs 2.11 ± 0.03, P 〈 0.05）. CONCLUSION： The viability and function of rat islets decrease over time in in vitro culture, and heine oxygenase-1 gene transfer could improve the viability and function of cultured rat islets.

Effect of human hepatocyte growth factor on promoting wound healing and preventing scar formation by adenovirus-mediated gene transfer

Objective To evaluate the effects of hepatocyte growth factor (HGF) on the prevention of scar formation and the promotion of wound healing by gene transfer Methods A total of 12 female New Zealand rabbits were used in this study Rabbits were anesthetized with an intravenous injection of sodium pentobarbital, and identical wounds were made over the ventral surface of each ear Five circular wounds, 7 mm in diameter, were created in each ear by excision through the skin to the underlying cartilage using sterile technique After the surgical procedures, 10 of the rabbits were randomly allocated to five groups, with 2 rabbits in each group: Ad HGF group 1, Ad HGF group 2, Ad HGF group 3, Ad GFP (a reporter gene) group and the solvent group Immediately after surgery, 6×10 7 pfu Ad HGF, 6×10 8 pfu Ad HGF, 6×10 9 pfu of Ad HGF, 6×10 9 pfu of Ad GFP, or same volume of solvent (PBS, pH 7.2) was applied once to each wound in groups 1 to 5, respectively One additional rabbit was used to evaluate the transfer efficiency of the adenovirus vector by transferring Ad GFP (6×10 9 pfu) into its wounds Ice slides of wounds from this animal were observed under fluorescence microscopy Another additional rabbit was used to evaluate the expression of HGF and TGFβ1 after transferring Ad HGF (6×10 9 pfu) into each of its wound Immunohistochemistry was used for detection Results The effect of HGF on reducing excessive dermal scarring was observed by adenovirus mediated gene transfer Transfection of the human HGF cDNA into skin wounds through an adenoviral vector suppressed the over expression of TGFβ1, which plays an essential role in the progression of dermal fibrogenesis Application of HGF to the wounds significantly enhanced wound healing and inhibited over scarring Conclusion HGF gene therapy could be a new approach for preventing excessive dermal scarring in wound healing