Therapeutic Effect of Alpha Lipoic Acid in a Rat Preclinical Model of Preeclampsia: Focus on Maternal Signs, Fetal Growth and Placental Function.

Chronic hypertension is a major risk factor for preeclampsia (PE), associated with significant maternal and neonatal morbidity. We previously demonstrated that pregnant stroke-prone spontaneously hypertensive rats (SHRSP) display a spontaneous PE-like phenotype with distinct placental, fetal, and maternal features. Here, we hypothesized that supplementation with alpha lipoic acid (ALA), a potent antioxidant, during early pregnancy could ameliorate the PE phenotype in this model. To test this hypothesis, timed pregnancies were established using 10 to 12-week-old SHRSP females (n = 19-16/group), which were assigned to two treatment groups: ALA (injected intraperitoneally with 25 mg/kg body weight ALA on gestation day (GD1, GD8, and GD12) or control, receiving saline following the same protocol. Our analysis of maternal signs showed that ALA prevented the pregnancy-dependent maternal blood pressure rise (GD14 blood pressure control 169.3 ± 19.4 mmHg vs. 146.1 ± 13.4 mmHg, p = 0.0001) and ameliorated renal function, as noted by the increased creatinine clearance and improved glomerular histology in treated dams. Treatment also improved the fetal growth restriction (FGR) phenotype, leading to increased fetal weights (ALA 2.19 ± 0.5 g vs. control 1.98 ± 0.3 g, p = 0.0074) and decreased cephalization indexes, indicating a more symmetric fetal growth pattern. This was associated with improved placental efficiency, decreased oxidative stress marker expression on GD14, and serum soluble fms-like tyrosine kinase 1 (sFlt1) levels on GD20. In conclusion, ALA supplementation mitigated maternal signs and improved placental function and fetal growth in SHRSP pregnancies, emerging as a promising therapy in pregnancies at high risk for PE.

Cellular Oxidative/Antioxidant Balance in γ-Irradiated Brain: An Update.

Both epidemiological and experimental data indicate that ionizing radiation (IR) may disrupt developmental processes leading to deleterious effects on brain functions. A central role of reactive oxygen (ROS) and nitrogen species (RNS), as important mediators in neurotoxicity and neuroprotection, has been demonstrated. Primary ionization events triggered by IR are amplified and propagated by mechanisms involving ROS and RNS, which activate several signaling pathways leading to final radiation effects. The immature and adult brain display clear differences in the way they respond to insults. Moreover, a great deal of attention is being focus on the limited antioxidant capacity and the particular lipid composition of cell membranes of the developing brain that render it more vulnerable to oxidative stress. The goal of this review is to summarize the current knowledge on the role of alterations in the balance between oxidative/nitrosative stress and antioxidant capacity in the pathways involved in cellular radiation response, with particular focus on the possible therapies proposed to limit radiation-induced effects in the brain.

Soybean ferritin: isolation, characterization, and free radical generation.

The main aim of this work was to assess the multi-task role of ferritin (Ft) in the oxidative metabolism of soybean (Glycine max). Soybean seeds incubated for 24 h yielded 41 ± 5 µg Ft/g fresh weight. The rate of in vitro incorporation of iron (Fe) into Ft was tested by supplementing the reaction medium with physiological Fe chelators. The control rate, observed in the presence of 100 µM Fe, was not significantly different from the values observed in the presence of 100 µM Fe-his. However, it was significantly higher in the presence of 100 µM Fe-citrate (approximately 4.5-fold) or of 100 µM Fe-ATP (approximately 14-fold). Moreover, a substantial decrease in the Trp-dependent fluorescence of the Ft protein was determined during Fe uptake from Fe-citrate, as compared with the control. On the other hand, Ft addition to homogenates from soybean embryonic axes reduced endogenously generated ascorbyl radical, according to its capacity for Fe uptake. The data presented here suggest that Ft could be involved in the generation of free radicals, such as hydroxyl radical, by Fe-catalyzed reactions. Moreover, the scavenging of these radicals by Ft itself could then lead to protein damage. However, Ft could also prevent cellular damage by the uptake of catalytically active Fe.

Labile iron pool and ferritin content in developing rat brain gamma-irradiated in utero.

This study was aimed to assess the content of total Fe, Ferritin (Ft) and labile Fe pool (LIP) in developing rat brain exposed in utero to 1 Gy of gamma-irradiation. A significant increase (2.3-fold) in the total Fe content of the fetal rat brain irradiated in utero was observed from 1 to 4h post-irradiation, as compared to the content in non-irradiated brain. Ft was analyzed by immunoblotting. The Ft protein was composed by 20 kDa subunits. According to the analysis of the band density in the Western blot, the Ft content decreased by 77+/-15% 2h after gamma-irradiation, as compared to the values in non-irradiated samples. The effect of gamma-irradiation on the LIP was studied by both electron paramagnetic resonance (EPR) and by a fluorescence technique employing calcein (CA). A reduction on the LIP was detected at 2h post-irradiation, independently of the methodology employed for the assay. Since NO content increased in the same time frame of LIP decreasing, a protective role for NO is suggested in fetal rat brain exposed to gamma-irradiation. The data presented in this work are the first experimental evidence suggesting that, as part of the network of the cellular response to limit irradiation-dependent injury, a complex interaction between Fe and NO could be triggered.

Reactive species and apoptosis of neural precursor cells after gamma-irradiation.

This study addresses the participation of radiation-induced free radicals, mainly nitric oxide (NO), in modulating the apoptotic response in an in vitro model of neural cortical precursor cells exposed to gamma-radiation. Cortical cells obtained from rats at 17 gestational day (GD) were irradiated with a dose of 2 Gy. The percentage of apoptotic cells was significantly increased 4h post-irradiation (pi). NO content showed a significant increase after 30 min pi and the rate of generation reached a maximum 1h pi. Luminol-dependent chemiluminescence (CL) was significantly higher in cells after 2h pi as compared to control cells and this profile was maintained up to 4 h pi. Supplementation with L-NAME significantly increased light emission. Administration of superoxide dismutase (SOD) following L-NAME addition prevented the observed changes due to L-NAME administration. The caspase inhibitor zDEVD-fmk significantly reduced the radical generation. Moreover, the cellular decrease in NO content occurred coincidentally with the rise in oxygen radical generation and the activation of caspase-3. In vitro irradiation of neural precursor cells allowed us to suggest that an early radiation-induced generation of NO could exert a neuroprotective role. However, despite this NO initial protective effect and its role modulating the response against gamma-radiation, NO generation was not able of fully preventing radiation-induced apoptosis.

Early neuroprotective effect of nitric oxide in developing rat brain irradiated in utero.

Pregnant Wistar rats were exposed on day 17 of gestation to 1 Gy gamma irradiation from a Co(60) source. Even though it is established that gamma radiation-dependent damage is mainly due to free radical generation neither the ascorbyl radical/ascorbate ratio nor the lipid radical content in developing rat brain were affected by prenatal irradiation. A distinctive EPR signal for the adduct NO-Fe-MGD (g=2.03 and a(N)=12.5 G) was detected in brain homogenates prepared from irradiated rats. Nitric oxide (NO)-dependent EPR signal increased in a time-dependent manner up to 2h post-irradiation. NO concentration in unirradiated brains was 37+/-4 pmol/g brain and 45+/-2, 77+/-5 and 216+/-6 after 30, 60 and 120 min post-irradiation, respectively. Total nitric oxide synthase activity was increased by 77 and 51% after 30 and 60 min post-irradiation, respectively, and returned to control values after 120 min. Thus, increased NO steady-state concentration could be ascribed to an increase in NOS activity. Taken as a whole, these results suggest that NO might act to protect the developing brain from the cytotoxicity of reactive species.