| Objective We have employed the rats with levels of different blood pressure to study the activity changes of NF-κB and ICAM-1 in endothelial dysfunction under ACE. In addition, 2k2c RHR with different levels of high blood pressure were examined to evaluate the contribution of endothelial cell adhesion molecules on the induction of stroke under the cold exposure.Methods Two-kidney-two-clip RHR were used in the present study. The sham-operated rats were undergone the same experimental procedures except for placement of clip, they (n= 24) served as normotensive controls. Normal sham-operated rats and 2k2c RHR were randomly assigned into 2 groups: ACE and non-ACE. Each group was further divided into 4 sub-groups according to their SBP (after 2k2c operation before the ACE treatment):①Sham-operated control group, BP<140mmHg,②mild hypertensive group, BP of 160-200mmHg,③moderate hypertensive group, BP of 200-220mmHg, and④severe hypertensive group, BP≥220mmHg. To establish the ACE and non-ACE treatment, the RHR were housed individually in a modified intelligent artificial climate cabinet. The ACE was designed as 3 cycles of 12 h light of 22℃and 12 h dark of 4℃. The non-ACE group was kept at 22℃throughout the experiment. Movement of limbs and consciousness of the rats were recorded twice daily during ACE and non-ACE treatment. Systolic BP (SBP), body weight were measured before and after ACE or non-ACE treatment. Afterwards, rat brains were removed quickly and then sectioned into 2.0-mm-thick coronal sections. 5.0-μm-thick paraffin sections or frozen sections from bregma section were stained with immunohistochemistry. Other sections were stained with HE to observe whether stroke occurred.Results 1.Blood pressures in different group generally decreased to some extent after ACE treatment compared with those before ACE treatment. For the sham-operated control rats (BP<140 mmHg), no rat has developed stroke under either the non-ACE or ACE conditions. In contrast, the 2k2c RHR as a whole exhibited 2.7% (1/36) incidence of stroke under the non-ACE conditions. 2.Moreover, ACE treatment further increased the stoke incidence to 22.2% (8/36, P < 0.01).3. NF-κB and ICAM-1 were measured in rats of stroke vulnerability but without stroke showed a similar trend as follows:the expression of NF-κB and ICAM-1 were different in rats of different blood pressure level, P<0.01;and them were different in rats of ACE and non-ACE, P<0.01;there are interaction between blood pressure level and different deal methods. a)In Bp <220mmHg subgroup, both indexes were elevated after ACE compared with those before ACE P<0.05; On the other hand, both the indexes in Bp≥220mmHg subgroup decreased to some extent after ACE treatment compared with those before ACE,P<0.05. b) Among rats with not-ACE treatment, there is a positive association between high blood pressure and both indexes. Among rats with not-ACE treatment, this positive association can also be seen in rats with Bp <220mmHg, however, Both indexes decreased dramatically in rats with Bp≥220mmHg compared with those with Bp <220mmHg, P<0.05. In addition, Both indexes in rats without stroke were different from those in rats with stroke.Conclusions Up-regulative expression of NF-κB and ICAM-1 may play a role in the onset of cerebral apoplexy in intracranial artery when RHR Induced by Artificial Cold Exposure.
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