The effects of tissue kallikrein on expressions of bradykinin and its receptors in ischemic brain tissue following cerebral ischemia-reperfusion in rats / 国际脑血管病杂志

ABSTRACT

Objective To investigate the effects of tissue kallikrein on expressions of bradykinin, bradykinin Bl receptor (B1R) and bradykinin B2 receptor (B2R) in ischemic brain tissue following cerebral ischemia-reperfusion in rats. Methods Fifty-four SD rats were randomly divided into three groups: sham operation, normal saline (NS) (2 ml · kg-1 · d-1, for 3 days), and TK (IK 175 × 10-3 U· kg-1 · d-1,for3 days) groups (n = 18 in each group). After three days,the neurological deficit score and the measurement of cerebral infarct volume were performed,The concentration of bradykinin in the ischemic region was detected by the enzyme- linked imrnunosorbent assay (ELBA).reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the mRNA and protein expressions of BlR, B2R in ischemic brain tissue, respectively. Results Compared with the NS group, the neurological deficit (6.17 ± 1. 17 vs. 8. 17 ± 1.33; t =2.000, P =0- 004) and the cerebral infarct volume (29. 67% ±3. 78% vs. 37. 50% ± 6. 72% ;t =0.078, P =0.005) in the TK group were reduced significantly; the concentration of bradykinin in ischemic brain tissue in the TK group was increased significantly (9.25 ± 1. 13 vs. 15.53 ± 1.68, t =6.283, P =0. 000); the expression of B2R mRNA was up regulated significantly (1. 21 ±0. 17 υs. 2.15 ±0.20; t =0.943,P =0- 000), but the up-regulation of the B2R mRNA expression was not obvious (0.51 ±0.05 υs. 0.57 ±0.06; t =0.058, P =0. 141); the expression of B2R protein in ischemic brain tissue was up-regulated significantly (1. 15 ±0. 16 vs. 1. 88 ± 0.21, t =0. 737, P =0. 000), but the up-regulation of BlR was not obvious (0. 50 ±0.04 vs. 0.53 ±0.05, t = 1.326, P =0. 214). Conclusions TK has protective effect on cerebral ischemia-reperfusion in rats. It may increase the bradykinin concentration in ischemic brain tissue, and up-regulate B2R expression, but it has little effect on Bl R expression.It is speculated that B2R may play a major role in TK protecting ischemic brain tissue.