Effect of strenuous maternal exercise before and during pregnancy on rat progeny renal function

Abstract

The effects of strenuous exercise before and during pregnancy on the renal function and morphological alterations of the progeny were determined in a study on female Wistar rats. This research was done based on a previous study carried out in our laboratory, which showed morphological alterations in rats submitted to this kind of exercise. As the form is related to the function, the physiological relevance of submitting a pregnant female to a high-intensity exercise training regimen could be explained by the fact that morphological alterations can influence kidney function. The animals were assigned to one of two groups: control animals that did not exercise during pregnancy and trained animals that swam for 120 min 5 days a week for 8 weeks before pregnancy and daily for 60 min over a period of 8 weeks starting on the second day of pregnancy. Seven rats of each group were analyzed for morphological alterations and for renal function. The progeny of the rats used for morphological evaluation were born by cesarean section and the progeny of the animals used to evaluate renal function were born normally. The progeny were two months old when renal function was evaluated. Fertility and morbidity were the same for both groups. Strenuous maternal exercise had no significant influence on glomerular filtration rate (GFR) but renal plasma flow was lower in the progeny of the trained group (mean ± SD, 16.65 ± 3.77 ml min -1 kg -1 ) compared to the progeny of the control group (33.42 ± 2.56 ml min -1 kg -1 ). Antidiuretic and antinatriuretic effects on the progeny of the trained group were observed, since urine flow as percentage of GFR and the fraction of urinary sodium excretion were lower in this group (1.38 ± 0.10 and 0.60 ± 0.04%, respectively) compared to the progeny of the control group (2.36 ± 0.11 and 1.55 ± 0.20%, respectively). Moreover, in this exercise program, fetuses from trained animals were small-sized (2.45 ± 0.19 vs 4.66 ± 2.45 g for control animals) and showed lower differentiation compared to fetuses from the control group. These effects were probably caused by caloric restriction, hypoxia and reduction of umbilical cord length.

Voluntary exercise in pregnant rats positively influences fetal growth without initiating a maternal physiological stress response

“…For example, birth weight of pups from treadmill-exercised dams was lower than from nonexercised dams in some studies (18,28,48), and treadmill exercise had no effect on birth weight in others (33). Birth weight of pups from pregnant rats that swam for 60 min/day was lower than (38), whereas birth weight of pups from pregnant rats that swam for only 10 min/day was not different from (1), that of pups from control animals. In addition, exercise during pregnancy may cause stress in experimental animals, providing a major confounder in the interpretation of results.…”

“…Additionally, neither exercise requires a nox-ious stimulus to the rats. This is in contrast to the treadmill running and swimming extensively described in pregnant rats (31,35,38,40); these exercises often involve noxious stimuli to the animals and are likely to require greater energy use than squat exercise or tower climbing. Previously, we demonstrated that voluntary tower climbing and squat exercise to obtain food are sufficiently strenuous to cause modeling of the tibia in nonpregnant rats without a concomitant rise in fecal corticosterone levels (43), a measure of stress in the rat.…”

Efeito do exercício físico contínuo e intervalado no peso e perfil bioquímico de ratas Wistar prenhes e consequências no peso da prole

“…Further studies with moderate and high intensity exercise models do not show differences between groups concerning birth weight. On the other hand, different reports show that moderate intensity exercises during pregnancy may increase birth weight, while more intense exercises with high frequency, kept for long periods during this phase, may result in children with low weight (26)(27)(28)(29)(30)(31) .…”

Moderate exercise attenuates lipopolysaccharide-induced inflammation and associated maternal and fetal morbidities in pregnant rats

“…high or low) may be a more effective option with broader outcomes. Indeed, there is evidence that differing exercise intensities during pregnancy have variable effects on maternal and neonatal health outcomes [41,42].…”