Abstract: Objective To investigate.the effect of S100B, AQP4, and CX43 on the function of the blood brain barrier in the hippocampus of diabetic rats with depression.Methods Rats were divided into the diabetic group(tow weeks of high-fat diet and injection of Streptozotocin (STZ, 38 mg/kg)), the depression group(chronic unpredictable stress for 28 days), the diabetes mellitus with depression group(combined with the above two methods to establish), and the control group.The behavior of rats were evaluated with Open-field test and Morris test. The expression of AQP4 and CX43 in rat hippocampul blood-brain barrier was detected by immunocytochemistry. S100B was detected by ELISA . Results Compared with control group , the number of autonomic activity and was the space exploration times were decreased, the escape latencies were significantly longer in the Morris water maze test(P<0.05 or P<0.01) of the diabetes group and depression group; Serum S100B levels increased significantly(P<0.01);the expression of AQP4 and CX43 was decreased(P<0.01). Compared with diabetic group , the number of autonomic activity and was the space exploration times were decreased, the escape latencies were significantly longer in the Morris water maze test(P<0.05 or P<0.01) of the diabetes group and depression group; Serum S100B levels increased significantly(P<0.05);the expression of AQP4 and CX43 was decreased(P<0.05 or P<0.01). Conclusions S100B, AQP4, CX43 expression disorder may be one of the mechanisms of diabetes mellitus complicated with depression.

Key words: Diabetes mellitus with depression, Blood-Brain Barrie, S100B, Aquaporin 4, Connexin 43