AIM:To study vascular endothelial growth factor(VEGF), pigment epithelium derived factor(PEDF)and hypoxia inducible factor-1α(HIF-1α)expression in retinal and serum in ozone-treated streptozotocin(STZ)-induced diabetic rats and to determine the possible efficacy of ozone therapy for diabetic retinopathy(DR).

METHODS:Seventy male Sprague-Dawley rats were used. Group A(n=10)received a normal diet, diabetic molding established by intraperitoneal injection of STZ(50mg/ml), then divided into three groups, group B without any intervene; and groups C and D given oxygen and ozone clyster treatment respectively, twice per week for 1mo. Retina and blood were taken under general anesthesia. Reverse transcription-polymerase chain reaction(RT-PCR)and enzyme-linked immunosorbent assay(ELISA)methods were used to study retinal and serum VEGF, HIF-1α and PEDF expression.

RESULTS:VEGF occurred mostly in the inner layer of the retina; the difference of VEGF in the retina among each group has statistical difference(F=23.923; P=0.000); in which, group D closer to group A, but still has statistical difference(P<0.05); there is no difference between group B and C(P>0.05)except for no difference between group A and D(P>0.05), others as same result as retinal VEGF expression.HIF-1α expression decreased in ozone-treated rats(group D)compared with control group(P<0.05); the difference between group A and groups B and C was significant(P<0.05), and the difference between groups B and C with no statistical difference(P>0.05). Overall, PEDF expression was lower than VEGF and HIF-1α, and groups A and D showed more expression than groups B and C, but the differences were not significant(P >0.05).

CONCLUSION: Ozone administration can reduce the VEGF and HIF-1α expression and ozone may have potential uses in its treatment.