CHOLINERGIC STIMULATION AFTER ACUTE MYOCARDIAL INFARCTION IMPROVES HEMODYNAMIC PARAMETERS AND MODULATES RENAL PROLIFERATIVE CELL ACTIVITY IN SPONTANEOUS HYPERTENSIVE RATS

Objective: Increased blood pressure may interfere with the hemodynamic response after acute myocardial infarction (AMI), and the exacerbated inflammatory process may reduce the immune response in spontaneous hypertensive rats (SHR) after AMI. Recently, it has been described that direct stimulation of the vagus nerve or the use of anticholinesterase drugs (pyridostigmine, PY) can reduce the inflammatory process in several models of inflammation. Little is known about the impact of PY on inflammation related to renal injury after AMI in the SHR model. Therefore, the objective was to investigate whether cholinergic stimulation by the administration of pyridostigmine improves hemodynamic parameters and cell proliferation in the kidney after AMI in the SHR model. Design and method: Adult male SHR rats were divided into 3 groups (8 animals/group): SHAM (submitted to thoracotomy), AMI (infarcted: thoracotomy with left coronary artery ligation), and AMI+PY (infarcted + treated with PY at a dose of 40 mg/kg/day, by gavage, for 7 days). On the sixth day, blood pressure curves were analyzed after direct recording by catheterization of the femoral artery. After euthanasia on the seventh day, the kidneys were removed for analysis of cell proliferation activity, measured by expression of PCNA using the immunohistochemistry technique. We used the ANOVA test for analysis between groups. Results: The AMI+PY group compared to SHAM presented lower values of SBP, DBP and MBP (SBP 182±7 vs 204.0±6, DPB 128±9 vs 144±9, MPB 156±7 vs 173±10) and lower DBP compared to AMI (128±9 vs 140±7). The AMI group compared to SHAM presented lower values of SBP and MBP (SBP 190.0±12.08 vs 204.0±6 and MPB 160±9.4 vs 173±10), respectively. The AMI+PY group presented lower expression of glomerular and interstitial PCNA compared to the SHAM group, while no differences were observed in comparison with the AMI group. Tubular PCNA was equally reduced in infarcted groups related to SHAM animals (p<0,05).Conclusions: Cholinergic stimulation improves hemodynamic parameters and reduces cell proliferation in the kidney after AMI in SHR rats.