Maternal Protein Restriction in Two Successive Generations Impairs Mitochondrial Electron Coupling in the Progeny's Brainstem of Wistar Rats From Both Sexes.

Maternal protein deficiency during the critical development period of the progeny disturbs mitochondrial metabolism in the brainstem, which increases the risk of developing cardiovascular diseases in the first-generation (F1) offspring, but is unknown if this effect persists in the second-generation (F2) offspring. The study tested whether mitochondrial health and oxidative balance will be restored in F2 rats. Male and female rats were divided into six groups according to the diet fed to their mothers throughout gestation and lactation periods. These groups were: (1) normoprotein (NP) and (2) low-protein (LP) rats of the first filial generation (F1-NP and F1-LP, respectively) and (3) NP and (4) LP rats of the second filial generation (F2-NP and F2-LP, respectively). After weaning, all groups received commercial chow and a portion of each group was sacrificed on the 30th day of life for determination of mitochondrial and oxidative parameters. The remaining portion of the F1 group was mated at adulthood and fed an NP or LP diet during the periods of gestation and lactation, to produce progeny belonging to (5) F2R-NP and (6) F2R-LP group, respectively. Our results demonstrated that male F1-LP rats suffered mitochondrial impairment associated with an 89% higher production of reactive species (RS) and 137% higher oxidative stress biomarkers, but that the oxidative stress was blunted in female F1-LP animals despite the antioxidant impairment. In the second generation following F0 malnutrition, brainstem antioxidant defenses were restored in the F2-LP group of both sexes. However, F2R-LP offspring, exposed to LP in the diets of the two preceding generations displayed a RS overproduction with a concomitant decrease in mitochondrial bioenergetics. Our findings demonstrate that nutritional stress during the reproductive life of the mother can negatively affect mitochondrial metabolism and oxidative balance in the brainstem of F1 progeny, but that restoration of a normal diet during the reproductive life of those individuals leads toward a mitochondrial recovery in their own (F2) progeny. Otherwise, if protein deprivation is continued from the F0 generation and into the F1 generation, the F2 progeny will exhibit no recovery, but instead will remain vulnerable to further oxidative damage.

Oxidative injuries induced by maternal low-protein diet in female brainstem.

Many studies have shown that a maternal low-protein diet increases the susceptibility of offspring to cardiovascular disease in later-life. Moreover, a lower incidence of cardiovascular disease in females than in males is understood to be largely due to the protective effect of high levels of estrogens throughout a woman's reproductive life. However, to our knowledge, the role of estradiol in moderating the later-life susceptibility of offspring of nutrient-deprived mothers to cardiovascular disease is not fully understood. The present study is aimed at investigating whether oxidative stress in the brainstem caused by a maternal low-protein diet administered during a critical period of fetal/neonatal brain development (i.e during gestation and lactation) is affected by estradiol levels. Female Wistar rat offspring were divided into four groups according to their mothers' diets and to the serum estradiol levels of the offspring at the time of testing: (1) 22 days of age/control diet: (2) 22 days of age/low-protein diet; (3) 122 days of age/control diet: (4) 122 days of age/low-protein diet. Undernutrition in the context of low serum estradiol compared to undernutrition in a higher estradiol context resulted in increased levels of oxidative stress biomarkers and a reduction in enzymatic and non-enzymatic antioxidant defenses. Total global oxy-score showed oxidative damage in 22-day-old rats whose mothers had received a low-protein diet. In the 122-day-old group, we observed a decrease in oxidative stress biomarkers, increased enzymatic antioxidant activity, and a positive oxy-score when compared to control. We conclude from these results that following a protein deficiency in the maternal diet during early development of the offspring, estrogens present at high levels at reproductive age may confer resistance to the oxidative damage in the brainstem that is very apparent in pre-pubertal rats.

Fish oil and treadmill exercise have age-dependent effects on episodic memory and oxidative state of the hippocampus.

There is a growing interest to better understand how lifestyle choices can improve memory functions. Treadmill exercise and long-chain n-3 polyunsaturated fatty acids found in fish oil are able to stimulate hippocampal antioxidant defenses and improve memory. The aim was to test whether fish oil and exercise can improve rat's performance on memory tasks and optimize hippocampal antioxidant state in an age-dependent manner. Therefore, young and adult rats were exercised and received fish oil during 4 weeks. The exercise was performed for 30 min/day, with the speed gradually increasing from the first to the last week. Afterwards, episodic memory was measured by the recognition of object identity and spatial location. Hippocampal oxidative state was investigated with the levels of malondialdehyde (MDA), carbonyls content, antioxidant enzymatic activity (superoxide dismutase (SOD), catalase (CAT)), and antioxidant nonenzymatic activity (reduced glutathione, sulfhydryl content). The adult rats treated with fish oil and exercise (FO&EX) were able to recognize object's shape and placement; however, FO&EX young rats had impaired spatial recognition (p < 0.05). The FO&EX young rats did not have reduced MDA or carbonyl content, though either fish oil or exercise reduced MDA (p < 0.05) and carbonyl levels (p < 0.01). Exercise increased SOD (p < 0.001) and CAT activities (p < 0.05), and fish oil enhanced SOD activity (p < 0.05) in young rats. At adulthood, exercise increased MDA levels (p < 0.05), and FO&EX reduced MDA (p < 0.001). Finally, exercise and fish oil improved nonenzymatic antioxidant defense (p < 0.05) only in adult rats. Results support age-dependent effects of fish oil and exercise on memory and oxidative state of the hippocampus during either neurodevelopment or adulthood.

Neonatal SSRI exposure improves mitochondrial function and antioxidant defense in rat heart.

Protein restriction during prenatal, postnatal, or in both periods has a close relationship with subsequent development of cardiovascular disease in adulthood. Elevated brain levels of serotonin and its metabolites have been found in malnourished states. The aim in the present study was to investigate whether treatment with fluoxetine (Fx), a selective serotonin reuptake inhibitor, mimics the detrimental effect of low-protein diet during the perinatal period on the male rat heart. Our hypothesis is that increased circulating serotonin as a result of pharmacologic treatment with Fx leads to cardiac dysfunction similar to that observed in protein-restricted rats. Male Wistar rat pups received daily subcutaneous injection of Fx or vehicle from postnatal day 1 to postnatal day 21. Male rats were euthanized at 60 days of age and the following parameters were evaluated in the cardiac tissue: mitochondrial respiratory capacity, respiratory control ratio, reactive oxygen species (ROS) production, mitochondrial membrane potential, and biomarkers of oxidative stress and antioxidant defense. We found that Fx treatment increased mitochondrial respiratory capacity (123%) and membrane potential (212%) and decreased ROS production (55%). In addition we observed an increase in the antioxidant capacity (elevation in catalase activity (5-fold) and glutathione peroxidase (4.6-fold)). Taken together, our results suggest that Fx treatment in the developmental period positively affects the mitochondrial bioenergetics and antioxidant defense in the cardiac tissue.

Serotonin modulation in neonatal age does not impair cardiovascular physiology in adult female rats: Hemodynamics and oxidative stress analysis.

AIMS: The present study investigates the effects of neonatal serotonin modulation in female rats on cardiac parameters related to hemodynamics and oxidative metabolism in the mature animal. MAIN METHODS: Female Wistar rat pups were administered daily subcutaneous injections of fluoxetine (Fx-treated group) or vehicle solution (Ct-group) from the 1st to 21st day of life. At 60days of age, animals from both groups were either used for cardiovascular evaluation or sacrificed for tissue collection for biochemical assays. KEY FINDINGS: We found that body weight in the Fx-treated group was less than that in the control. When analyzing hemodynamic parameters (i.e., arterial blood pressure, heart rate-HR, sympathetic and vagal tonus, or intrinsic HR), we did not observe significant difference in the Fx-treated group. Evaluating oxidative stress in brainstem and heart by measuring carbonyl content and malondialdehyde-MDA formation, we observe a decrease in carbonyl content only in the Fx-treated group (60.3%, in brainstem; 58.2%, in heart), without difference in the MDA levels. This observation is consonant with an increase in superoxide dismutase-SOD and catalase-CAT activity in brainstem and heart in the Fx-treated group (SOD: 82.7% and CAT: 23.7 in brainstem; SOD: 60.6%, and CAT: 40.7 in heart), with no changes in glutathione S-transferase activity and reduced glutathione levels. With regard to oxidative metabolism markers, citrate synthase activity was higher in brainstem in the Fx-treated group (20%). SIGNIFICANCE: Our data suggest that serotonin modulation by Fx-treatment at an early age does not induce hemodynamic alteration, although it modulates oxidative metabolism in cardiac-related tissues.