Impact of gonadectomy on blood pressure regulation in ageing male and female rats

Figures

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  Fig. 1. Kidney function. a Glomerular filtration rate (GFR) based on the creatinine clearance over a 24-h period and adjusted for the body weight of the animal showed decline in renal function with ageing (6, 12 > 18 months of age, P < 0.01). Females had higher GFR than males (P < 0.05). b The plasma urea concentration was unaffected by either ageing or surgery although there was a tendency towards change in the concentration of urea with age after gonadectomy P = 0.068. c Albuminuria was higher in males vs. females (P < 0.01) and the amount of albumin excreted increased with age (6, 12 < 18 months of age, P = 0.01), though this effect was largely confined to males. d Proteinuria was higher in males vs. females (P < 0.001). Proteinuria also increased with age in males (6 < 12, 18 months of age, P < 0.05). The INTACT animals had higher proteinuria than the GONADX, and this was significantly reduced by castration (P < 0.001). Data are presented as mean ± SEM for n = 8 per group,*P < 0.05; **P < 0.01; ***P < 0.001

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  Fig. 2. Inflammatory markers. Immunohistochemistry on the left sectioned kidney shows CD3 (a) and ED1 (b) inflammatory markers expressed as positive cells per glomerulus of the kidney. CD3, a T cell marker, was increased in the glomeruli at 6 months compared to that of 12 and 18 months of age, P < 0.01. ED1, a monocyte and macrophage marker, was increased in the glomeruli at 6 months compared to that of 12 and 18 months of age, P < 0.01. There were no influences of gonadectomy. Data are presented as mean ± SEM for n = 8 per group, ***P < 0.001

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  Fig. 3. Representative images of inflammatory markers. Representative images of CD3 (a) and ED1 (b) in glomerulus of the left sectioned kidney at 6, 12 and 18 months of age

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  Fig. 4. AGTR1 and AGTR2 protein expression. Kidney cortex protein level of AGTR1 (a) and AGTR2 (b) was assessed by Western blotting, and the AT1/AT2 (c) ratio presents a change of these receptors at 6, 12 and 18 months of age in relation to surgery. The AGTR1/AGTR2 ratio was significantly increased at 6 months of age, P < 0.05. Data are presented as mean ± SEM for n = 8 animal per group, *P < 0.05; ***P < 0.001

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  Fig. 5. Mean arterial blood pressure (mmHg) and heart rate (bpm) assessed telemetrically. Arterial blood pressure and heart rate were assessed telemetrically at 12 months of age. Females had a lower systolic blood pressure than males (SBP (a)), P < 0.05. The diastolic blood pressure (DBP (b)) was lower in females (P < 0.001) and in sham animals (P < 0.05), and there was an effect of ovariectomy (P < 0.01). Females mean heart rate (HR (c)) was significantly higher than all other groups (P < 0.001), and this was reduced by ovariectomy (P < 0.01). Additionally, sham animals had higher HR than gonadectomised rats (P < 0.05). Data are presented as mean ± SEM for n = 8 animal per group,*P < 0.05; **P < 0.01; ***P < 0.001

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  Fig. 6. Mean arterial blood pressure (mmHg) and heart rate (bpm) measured by tail-cuff system CODA. The SBP (a) and DBP (b) was decreased by castration that was more pronounced at 18 months of age (interaction age × surgery, P < 0.05). There was a significant increase in the heart rate (HR; c) in the M-GONADX at 18 months of age, P < 0.05. Data are presented as mean ± SEM for n = 8 animal per group,*P < 0.05