Development of myocardial hypertrophy in normetensive rats.

8. AIELLO EA, VILLA-ABRILLE MC, PÉREZ NG, CAMILIÓN DE HURTADO MC, ESCUDERO EM, CINGOLANI HE

La Plata, Argentina

Congreso; X meeting of the ISHR Latin American Section; 2002

The correlation between blood pressure (BP) and cardiac hypertrophy (CH) is not high. This implies that we can find patients with normal or high levels of BP with CH and patients with high BP without much CH. In our studies with SHR, WKY and Wistar rats, we observed WKY normotensive rats with CH determined by greater heart weight/body weight ratio (hypertrophy index HI) than that of Wistar normotensive rats. In order to bring new insights into the matter we compared, in SHR, WKY and Wistar rats, the following parameters: HI, cell capacitance (C) as index of total surface area of the myocytes and length (L) and width (W) of the myocytes. C was measured in whole-cell configuration of patch-clamp technique and L and W were measured with cell edge detector. The table shows the results obtained. The n values are presented between brackets besides each value.   BP(mmHg) HI(mg/g) C(pF) L(mm) W(mm) Wistar 113±4(8) 2.7±0.1(7) 124±13(14) 126±3(20) 30±1(23) WKY 118±4(9) 3.2±0.1(6) 206±15(16) 132±4(22) 38±2(22) SHR 178±3(9) 3.4±0.1(10) 236±25(9) 146±4(31) 32±1(31) The HI and C were similar in SHR and WKY rats, both parameters being significantly higher than those of Wistar. L was smaller but W was greater in WKY in comparison to SHR. These findings demonstrated CH in normotensive WKY rats. Since the values of BP are normal, this CH present in WKY rats cannot be caused by pressure overload. This phenomenon could be likely explained by possible alterations in rennin-angiotensin system at cardiac tissue level.