Physiological And Biochemical Studies Of Ageing Rat Heart With Experimental Arterial Hypertension

Objective: It has been shown that DOCA-NaCl dependent arterial hypertension appears before any kidney lesions and there are proofs which suggest the role of NaCl retention or sensitivity to this in etiology of essential arterial hypertension The aim of our study was concerned with evaluation of physiological and biochemical parameters of rat heart with arterial hypertension experimentally induced with (DOCA) as well as to investigate the antioxidant potential and lipid metabolism parameters. Design and method: 16 white male Wistar rats (180 + 20 g), aged 20 months old, fed on standard chew, have been divided into two groups of 8 rats each: group A Controls and group B treated with DOCA for 4 weeks with 2 (i .m.) injections /week) with 10 mg/kg b.w. and two weeks afterwards drinking water has been replaced by saline solution (0.9%NaCl + 0.2%KCl). Evaluation of physiological parameters: heart rate (H.R.), coronary flow (C.F.) and left ventricle systolic pressure (L.V.S.P.) of heart from controls and hypertensive rats has been achieved on isolated heart in Langendorff perfusion system with Krebs Hanseleit bicarbonate buffer at a constant pressure. Oxidative stress has been imposed by applying a 45 minutes ischemia which has been followed by 120 minutes reperfusion. Biochemical studies of antioxidant system have been performed on plasma and left ventricle tissue by evaluating: SOD, GGT, Lipid peroxides, CK, LDH, Cholesterol, LDL, HDL with standard biochemical methods. Results: Our data have pointed out that for about one hour (C.F.) presented higher values as well as (LVSP) and (H.R). in DOCA treated rats, above the values from Controls. These data account for an intense cardiac activity imposed by the onset of arterial hypertension following DOCA treatment. A reduction in GGT in myocardium due to hypoxia generated by cardiac insufficiency following DOCA treatment is accompanied by a reduction of antioxidant potential and both HDL and CK markers of myocardial lesion exhibited higher values. Conclusions: Following 4 weeks DOCA treatment a pathological state is achieved similar with Essential arterial hypertension found in humans, accounted for by the following changes: an intensification of contractile activity, cardiac hypertrophy and the increase in lipid peroxides level, LDH and CK activity.