Effects of diabetes on the expression and function of bradykinin 1 and 2 receptors after cerebral ischemia/reperfusion in rats / 医学研究生学报

ABSTRACT

Objective There is little research focusing on the expression and function of bradykinin 1 receptor ( B1R ) and bradykinin 2 receptor ( B2R) after cerebral ischemia/reperfusion on the basis of diabetes .The aim of this study was to compare the ex-pression difference and function change of B 1R and B2R in non-dia-betic and diabetic rats . Methods The cerebral ischemia/reperfu-sion model was established on 41 non-diabetic and type 2 diabetic rats, the weight and the biochemical index were measured on these two types of rats .8 non-diabetic rats and 8 diabetic rats were respec- tively assigned to two groups according to random number tablescontrol group and I/R 24 h group, 4 in each group.Real-time PCR was performed to observe the expressions of two receptors at 24 h after reperfusion .Then, 33 non-diabetic rats and 33 diabetic rats were randomly divided into 4 groups respectively, including sham group (n=6), saline group (n=9), B1R antagonist group (n=9) and B2R antagonist group (n=9).At 24 hours after cerebral I/R, neurological deficiency was evaluated by neurological severity scores ( NSS);infarct volume was observed by TTC staining;cell apoptosis was determined by TUNEL staining;neuron degeneration was de-tected by Fluoro-Jade C staining. Results Glucoses of diabetics at 3, 7, 14 d after model establishment [(23.45 ±5.01), (23.71 ±4.87), (22.72 ±4.11) mmol/L] were obviously elevated compared with non-diabetics [(5.77 ±0.75), (6.05 ±0.69), (7.15 ±1.09) mmol/L];blood cholesterin [(4.59 ±3.43) mmol/L] and insulin [(67.26 ±12.02) pmol/L] at 14 d after model establishment were evidently incresaed in comparison to those in non-diabetics [(1.58 ±0.37) mmol/L, (25.34 ±4.88) pmol/L] (P0.05).Compared with non-diabetics, diabetics suffered from more apparent up-regulation of B1R mRNA (P<0.01) but relatively less B2R mRNA (P<0.05) at 24 h after I/R.NSS score, infarction volume, damaged and apoptotic cells in B2R antagonis-treated non-diabetic rats at 24 h after I/R conspicuously decreased compared with saline-treated non-daibetic rats.Those indicators in B1R antagonis-treated diabeics were strikingly lessened compared with saline-treated daibetics . Conclusion I/R induced distinct up-regulation of B2R mRNA in non-diabetics and inhibiton of B 2R effectively ameliorated the infarct volume and cell injury after I/R in non-diabetics; I/R induced more notable up-regulation of B1R mRNA in diabetics and B1R antagonist exerted neuroprotective effects instead of B 2R antagonist af-ter I/R in diabetics.