Effect of cross‐fostering on renal anti‐oxidant/oxidant status and development of hypertension in spontaneously hypertensive rats

Abstract

1. The hypotensive effect of cross-fostering in spontaneously hypertensive rats (SHR) is thought to involve adjustments in renal function. However, its association with renal anti-oxidant/oxidant balance during cross-fostering is not known. 2. The present study examined the effect of cross-fostering and in-fostering of 1-day-old offspring between SHR and Wistar-Kyoto (WKY) dams on renal anti-oxidant/oxidant status and systolic blood pressure (SBP). Renal anti-oxidant/oxidant status and SBP were determined in the offspring from 4-16 weeks of age. 3. Cross-fostered SHR had significantly lower SBP than in-fostered SHR at 6, 8 and 12 weeks, but not at 16 weeks (127 ± 1 vs 144 ± 2, 138 ± 1 vs 160 ± 1, 174 ± 2 vs 184 ± 2 and 199 ± 2 vs 194 ± 3 mmHg at 6, 8, 12 and 16 weeks, respectively). No differences in SBP were evident between cross-fostered and in-fostered WKY rats. There were no significant differences in levels of thiobarbituric acid-reactive substances (TBARS), protein carbonyl and total anti-oxidant status (TAS) or superoxide dismutase, catalase, glutathione peroxidase (GPx), glutathione S-transferase and glutathione reductase activity between cross-fostered and in-fostered SHR or WKY offspring. However, compared with WKY rats, catalase activity was higher at 6 and 16 weeks, TAS was higher at 16 weeks and GPx activity and TBARS were lower at 16 weeks in SHR. 4. It appears that cross-fostering of SHR offspring to WKY dams during the early postnatal period causes a transient delay in the rise in blood pressure in SHR and that this does not involve the renal anti-oxidant/oxidant system.

Assisted reproductive technologies and arterial hypertension

“…The works on cross fostering between SHR and WKY rats (Cierpial and McCarty, 1987;McCarty and Lee, 1996;Di Nicolantonio et al, 2006;Lee and Azar, 2010;Lee et al, 2011), in spite of the differences in the experimental design, had quite a reproducible result. The blood pressure in animals with SHR genotype, brought up by adaptive mothers of normotensive strain, was lower than in the case of upbringing by bio logical parents.…”

“…In addition, milk of SHR and WKY rats differed in the composition; an increased content of sodium chlo ride, as well as a decrease in potassium, calcium, and protein were found in milk of SHR rats (McCarty and Tong, 1995). However, the fact that SHR females secrete considerably less milk than WKY females dur ing the first two first weeks of the feeding period is con sidered to be the most significant factor (Gouldsbor ough et al, 1998;Ashton, 2000;Lee et al, 2011). These facts confirm the hypothesis that the role of postnatal maternal environment in the development of hypertension is mainly mediated through the amount and quality of milk.…”

“…A change in quantitative indices of milk production was demonstrated for nursing SHR females (Goulds borough et al, 1998;Ashton, 2000;Lee et al, 2011). In addition, milk of SHR and WKY rats differed in the composition; an increased content of sodium chlo ride, as well as a decrease in potassium, calcium, and protein were found in milk of SHR rats (McCarty and Tong, 1995).…”

“…At the same time, WKY rats brought up by SHR mothers did not become hypertensive, and their blood pressure did not differ from the control. Along with the influence on the blood pressure, cross fostering had an effect on the animal weight and other physiological characteristics (McCarty and Lee and Azar, 2010;Lee et al, 2011).…”