Objective: To observe the effects of water extract from cortex of Berberis dictyophylla (BDCE) on expressions of retinal protein kinaseC-β(PKC-β)

hypoxia inducing factor-1α(HIF-1α)

vascular endothelial growth factor(VEGF) in spontaneous type 2 diabetic db/db mice

in order to explore its mechanism in preventing and treating diabetic retinopathy (DR). Method: Eighteen-week-old db/db mice were selected

with their thin db/m mice for normal control group. The db/db mices were randomly divided into 6 groups:model control (db/db) group

high

middle and low-dose BDCE group (1.50

0.75

0.38 g·kg-1)

calcium-dobesilate group (0.23 g·kg-1)

and berberine hydrochloride group (0.135 g·kg-1). The mice were given relevant drugs for consecutively two months. At the end of the two-month treatment

all the mice were put to death. The immunohistochemical method was used to observe the expressions of the three factors on the retina. Real-time quantitative PCR and western blot methods were used to detect genes and proteins expressions level of PKC-β

HIF-1α and VEGF in retina. Result: Compared to db/m group

the immunohistochemical results showed positive reaction of PKC-β and VEGF in retinal tissues of db/db group

with significant increase in expressions (P<0.01); positive reaction of HIF-1α

with no significant increase in expressions of db/db group; mRNA and protein expressions of PKC-β

HIF-1α

VEGF increased significantly in db/db group (P<0.01). Compared to db/db group

the immunohistochemical results showed positive reaction of PKC-β on retinal tissues in calcium-dobesilate group

with significant decrease of expression (P<0.05); positive reaction of PKC-β on retinal tissues in high-dosage BDCE group

with significant decrease of expression (P<0.01); a downward trend in PKC-β expression in other treatment groups compared with the db/db group

with no statistical significance in difference; positive reaction of HIF-1α on retinal tissue in all treatment groups

with no significant decrease of expression; positive reaction of VEGF on retinal tissues in berberine hydrochloride group and low-dose BDCE group

with significant decrease of expression (P<0.01); and positive reaction of VEGF on retinal tissue in all other treatment groups

with no significant decrease of expression. Compared with db/db group

real-time quantitative PCR results showed significant decreased mRNA expressions of HIF-1α in calcium-dobesilate group (P<0.05)

decreased PKC-β

HIF-1α

VEGF mRNA expressions in other treatment groups

with no significant decrease. Compared with db/db group

Western blot results showed significant decreased protein expressions of PKC-β in calcium-dobesilate group

berberine hydrochloride group

and high and low-dose BDCE groups (P<0.01)

and slightly decreased protein expressions of PKC-β in middle-dose BDCE group

with no significant decrease. Western blot results showed significant decreased protein expressions of HIF-1α in calcium-dobesilate group

berberine hydrochloride group

high and middle-dose BDCE groups (P<0.01)

slightly decreased protein expressions of HIF-1α in BDCE low-dose group

with no significant decrease; Western blot results showed significant decreased protein expressions of HIF-1α in all treatment groups (P<0.01). Conclusion: BDCE was an efficient Tibetan medicine to prevent and treat DR

whose mechanism may be correlated with inhibition the expressions of PKC-β

HIF-1α

VEGF.