Objective      To study the effect of diazoxide (DIZ)-interfered oxidative stress on expression of SUR1 subunit gene in adenosine triphosphate sensitive potassium (KATP) channel of INS-I cells.      Methods      INS-1 cell strains were divided into oxidative stress group

DIZ interfere group

taurine interfere group

and control group. H

2

O

2

was added into INS-1 cell strains of oxidative stress group at the concentration of 50 μmol/L

100 μmol/L

200 μmol/L

and 400 μmol/L respectively

and cultured for 3 h. DIZ was added into INS-1 cell strains of DIZ interfere group at the concentration of 50 μmol/L and incubated for 30 min

then DIZ was added at the concentration of 400 μmol/L and incubated for an additional 3 h. Taurine was added into INS-1 cell strains of taurine interfere group at the concentration of 1μmol/L and incubated for 30 min

then H

2

O

2

was added at the concentration of 400 μmol/L and cultured for an additional 3 h. No DIZ

taurine

and H

2

O

2

were added into INS-1 cell strains of control group. Survival rate of INS-1 cell strains

glucose  simulated insulin secretion (GSIS) level

and SUR1 subunit protein expression level were measured by MTT assay

ELISA

and Western blotting

respectively

in oxidative stress group

DIZ interfere group

and taurine interfere group.      Results      The survival rate of INS-1 cell strains [(105.27±3.83)%

]

was significantly higher in oxidative stress group than in control group after exposed to 50 μmol/L H

2

O

2

(P0.05) and gradually decreased with the increased concentration of H

2

O

2

.  The survival rate of INS-1 cell strains was 68.66% and 51.67%

respectively

in oxidative stress group after exposed to 200 μmol/L a

nd 400 μmol/L of H

2

O

2

which was significantly lower than that in control group (P0.05). The GSIS level was higher in oxidative stress group than in control group after exposed to 50 μmol/L H

2

O

2

(118.47±10.15 mU/L vs 112.87±9.28 mU/L

P0.05) and gradually decreased with the increased concentration of H

2

O

2

.  The GSIS level was significantly lower in oxidative stress group than in control group after exposed to 200 μmol/L and 400 μmol/L of H

2

O

2

（64.59±4.53 mU/L vs 85.79±7.03 mU/L

P0.05）. The expression level of SUR1subunit protein in INS-1 cells was higher in oxidative stress group than in control group  after exposed to 50 μmol/L H

2

O

2

for 3 h and significantly higher in DIZ group than in control group after exposed to 200 μmol/L and 400 μmol/L H

2

O

2

for 3 h（P0.05）. However

no significant difference was observed between taurine interfere group and control group（P0.05）.     Conclusion    DIZ inhibits the expression of SUR1 subunit gene in K

ATP

channel of INS-I cells by suppressing the release of ROS through inhibiting the electronic transport in respiration chain of mitochrondria

thus reducing the oxidative stress of INS-I cells.