2022 Volume 47 Issue 5 Pages 183-192
Maternal lead exposure is associated with poor outcomes in fetal brain development such as cognitive dysfunction. Here, we aimed to reveal the effect and mechanism of omega-3 fatty acids in ameliorating maternal lead exposure-induced cognitive impairment in mouse offspring. The activity levels of locomotor and anxiety, memory and learning capacity, spatial working memory, and cognitive behavioral function were determined using the open field test, Morris water maze, Y-maze, and nest-building test, respectively. The protein levels of brain-derived neurotrophic factor (BDNF), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were measured using enzyme-linked immunosorbent assay or Western blot. The mRNA levels of BDNF, tyrosine kinase B (TrkB) and cyclic AMP response element binding protein (CREB) were measured by real-time qPCR. Malondialdehyde (MDA) and anti-oxidants, including SOD, GSH and CAT, were measured using bioassay kits. We found that supplementing omega-3 significantly improved cognitive behavioral function in offspring after prenatal lead exposure. The protein and mRNA levels of BDNF, TrkB and CREB in the prenatal lead exposure group were significantly upregulated by omega-3 supplementation. The MDA level in the prenatal lead exposure group was markedly elevated compared with the control group, which was significantly reduced by omega-3. Omega-3 restored anti-oxidants SOD, GSH and CAT to control levels after prenatal lead exposure. Omega-3 significantly upregulated Nrf2 nuclear expression and HO-1 expression after prenatal lead exposure. Overall, omega-3 supplementation significantly elevated the BDNF/TrkB/CREB pathway and restores anti-oxidants by upregulating the Nrf2/HO-1, thereby improving cognitive function in offspring after prenatal lead exposure.
Lead poisoning, caused by lead paint chip, leaded gasoline, etc., remains a problem in both developing and developed countries, negatively impacting children worldwide (Guidotti and Gitterman, 2007; Liu et al., 2014a). A small amount of lead exposure can severely damage the nervous system, delay cognition and memory and cause loss of peripheral nerve function (Bellinger et al., 1987). The side effects of lead exposure during pregnancy are a major health problem for women (Liu et al., 2014b; Skröder et al., 2015). Children are extremely vulnerable to maternal lead exposure, which could cause teratogenic effects, resulting in low birth weight and delayed mental development (Murata et al., 2009). In addition, studies have shown that exposure to lead during development can cause neurotoxic effects in the final steps of differentiation and synapse formation and brain development (Hu et al., 2006; Huang and Schneider, 2004). Therefore, developing an effective approach to protect the fetus from maternal lead exposure-induced neurotoxicity is needed.
A clinical study has demonstrated that prenatal and postnatal exposure to as low as 5 μg/dL lead could damage fetal neurodevelopment, resulting in neurocognitive impairment in children (Liu et al., 2014a). Exposure to lead is associated with unbalanced oxidants and anti-oxidants, inducing oxidative stress. A study has shown an upsurge of oxidative stress during maternal lead exposure, which further triggers apoptosis and ultimately causes cognitive impairments in the offspring (Hossain et al., 2016). Treatment with anti-oxidants showed a significant protective effect against maternal lead exposure-induced abnormal brain development (Antonio-García and Massó-Gonzalez, 2008). These results highlight that targeting anti-oxidants could serve as an effective strategy to prevent and manage maternal lead exposure-induced neurotoxicity in offspring.
The nuclear factor erythroid 2 related factor 2 (NRF2) plays an essential role in regulating gene expression involved in oxidative stress, thereby protecting the brain from stroke, ischemia-reperfusion, etc. Upregulating Nrf2 activation has been reported to stimulate anti-oxidant enzymes, thereby reducing oxidative stress in brain injury, suggesting that Nrf2 acts as a promising target to alleviate brain injury (Ding et al., 2014).
Omega-3 polyunsaturated fatty acids (n-3 PUFA) consist of docosahexaenoic acid (DHA), eicosatetraenoic acid (EPA) and docosapentaenoic acid (DPA) (Calon and Cole, 2007; Zhang et al., 2011). Several studies have consistently shown that omega-3 fatty acid deficiency is correlated with memory deficits and impaired hippocampal plasticity (Tyrtyshnaia et al., 2020; Bonhomme et al., 2014). Supplementing omega-3 fatty acid exerts neuroprotective effects, such as improving neurogenesis and synaptogenesis, executive function and learning ability (Ruxton et al., 2007; Shahidi and Ambigaipalan, 2018; Cutuli et al., 2016). Notably, omega-3 has been shown to reduce oxidative stress in the brain by inhibiting free radical and stimulating antioxidant enzymes gene expression (Ali et al., 2014; Saada et al., 2014).
In the current study, we aimed to investigate whether omega-3 fatty acid supplementation exhibited a neuroprotective effect on prenatal lead exposure in the mouse offspring. In addition, we aimed to gain insight into the mechanisms of omega-3 fatty acid in improving cognitive function in the offspring after prenatal lead exposure.
Two female C57BL/6 mice were housed with one male at the beginning of the dark period. The presence of a copulatory plug in the morning after mating indicated pregnancy and was considered as gestation day (GD) 0. Maternal mice were exposed to lead (PbAc) via drinking water (250 ppm) ad libitum starting at GD 5 until postnatal day (PND) 14. Omega groups were supplemented orally with a volume of 0.015 mL of fatty acids mixture (360 mg/kg/day of n-3 PUFA, mainly constituted by EPA (20:5 n-3; 63%), DHA (22:6 n-3; 26%), DPA (22:5 n-3; 4%), and a-linolenic acid (ALA, 18:3 n-3; 1%)) (Pfizer Inc., NY, USA) (Calviello et al., 1997; Cutuli, 2014) for 31 consecutive days starting at GD3. After weaning at PND21, two males were removed from each litter and combined with pups from other litters and served as the study population. Animal studies were approved by Daqing Oilfield General Hospital.
Open field testThe activity levels of locomotor and anxiety were measured using the open field apparatus (Kuramoto et al., 2019). The camera was fixed one meter above the stage to track the movement of a single mice placed in an opaque acrylic container, including speed, distance and image. After 1 min of acclimatization, the behavior of each mouse was recorded for 5 min. The time spent in the central region was recorded to assess the anxiety of the mice.
Morris water maze testMemory and learning capacity were assessed using Morris water maze (Qi et al., 2016). Morris water maze consisted of a round black pool (22 ± 2°C) and a hidden platform in a fixed position. Each mouse was given 60 sec to find the platform, and after staying on the platform for 15 sec. Then, the mouse was placed in a cage to dry for the next experiment. After completing all the tests on the 5th day, the platform was removed, and a 60 sec probe trial was performed. A camera was hung over the maze to track the path of each mouse, and a tracking system (Ethovision 3.1, Noldus Instruments) was used to analyze the track of each mouse. The swimming path distance (cm) and escape latency (sec) to the platform were measured to assess Morris water maze performance.
Y-maze testSpatial working memory was assessed using the Y-maze test. One of the three arms was closed, and each mouse was trained to move through the other two arms for 8 min. After an interval of 30 min, the closed arm was opened, and each mouse was allowed to move freely in all three arms for 8 min. The number of entries into each arm was recorded using Y-maze system (Muromachi Kikai). The percentage of novel arm entries was calculated as a ratio of the number of novel arm entries/the total number of all arm entries.
Nest-building testNest-building test was used to assess cognitive behavioral function. The mice were placed in separate cages, and a pressed cotton block was placed inside at 7 pm. The nesting results were scored as follows: (Deacon, 2006) 1) one piece of cotton was not touched obviously (more than 90% integrity); 2) the cotton was partially torn (50%–90% intact); 3) most of the cotton was torn (10%–50% intact), but no obvious nesting; 3.5) most of the cotton was torn (10%–50% intact) and was identifiable, but the flat nest was kept; 4) most cotton was torn (retained < 10% intact) and had a flat nest; 4.5) most of the cotton was torn (10%–50% intact) and a bowl nest was made; 5) most cotton was torn with bowl nests (< 10% remain intact).
Enzyme-linked immunosorbent assay (ELISA)Cortex and hippocampal homogenates were used to estimate the level of brain-derived neurotrophic factor (BDNF) by ELISA (Promega, Madison, WI, USA). The kit is designed to measure total free BDNF, which is estimated by Lowry method. The content of BDNF was expressed as pg/mg protein.
Real-time qPCRTotal mRNA was extracted using TRIzol reagent (Invitrogen, Carlsbad, CA, USA). cDNA was synthesized using the primeScript RT reagent kit (Takara Biotechnology, Dalian, China). Next, real-time qPCR was performed using a SYBR premix Ex Taq protocol (Takara Biotechnology) by an Agilent Stratagene M × 3005P apparatus (Agilent Technologies, Santa Clara, CA, USA). Relative expression was normalized to GAPDH and calculated using the comparative cycle threshold (CT) method. The primers were designed using Primer 3.0 software. The following primers were used: GAPDH: forward: 5′-AATGGATTTGGACGCATTGGT-3′, reverse 5′- TTTGCACTGGTACGTGTTGAT-3′; BDNF: forward: 5′-TCATACTTCGGTTGCATGAAGG-3′, reverse: 5′-ACACCTGGGTAGGCCAAGTT-3′; tyrosine kinase B (TrkB): forward: 5′- CTGGGGCTTATGCCTGCTG-3′, reverse: 5′-AGGCTCAGTACACCAAATCCTA-3′; cyclic AMP response element binding protein (CREB): forward: 5′-ACTCCAACGCCAACAAGATTC-3′, reverse: 5′- TCTACAACAGAAGGCTCCTCAAT-3′.
Western blotThe protein in the brain was extracted using the nuclear and cytoplasmic protein extraction kit (Beyotime Biotechnology, Haimen, China) according to the manufacturer’s manual. The protein concentration was determined using the BCA protein assay (Thermo, Waltham, MA, USA). The proteins were separated by electrophoresis on SDS-PAGE and transferred to nitrocellulose membrane at 75 V for 120 min. After blocking with 5% non-fat milk, the membrane was incubated with primary antibodies against Nrf2, heme oxygenase-1 (HO-1), lamin B and GAPDH, respectively, overnight at 4°C, followed by incubation for 1 hr at room temperature with horseradish peroxidase-conjugated secondary antibody. The blots were imaged using the SuperSignal West Pico PLUS Chemiluminescent Substrate (Thermo) and quantified using AlphaEaseFC Software (Witec, Littau, Switzerland).
Oxidative stress parameters analysisThe whole brain tissue was homogenized in ice-cold saline containing protease inhibitors (Cell Signaling Technology, Beverly, MA, USA) using a vitreous homogenizer, and then centrifuged at 4°C (3,000 rpm) for 10 min. The content of malondialdehyde (MDA), and the activity of superoxide dismutase (SOD), and the contents of glutathione (GSH) and catalase (CAT) were determined using the TBARS assay kit (Cell Biolabs, Inc., San Diego, CA, USA), superoxide dismutase assay kit (Cayman Chemical, Ann Arbor, MS, USA), glutathione assay kit (Cayman Chemical), and catalase assay kit, respectively. Protein concentrations were measured using a BCA assay kit.
Statistical analysisThe difference was assessed by one-way ANOVA with Dunn’s multiple comparisons test, or two-way ANOVA with Tukey’s multiple comparisons test in GraphPad prism 7. Data represented mean ± SD. A p value < 0.05 was considered statistically significant.
The activity levels of anxiety and locomotor were analyzed using open field test. Locomotion counts and the time spent in the central area showed no significant change between the control group and control treated with omega-3 fatty acid. However, significantly increased locomotion (p < 0.05) and decreased time spent in the central area were observed in the prenatal lead exposure (PbAc) group (p < 0.05, Fig. 1a). Notably, treatment with omega-3 markedly reduced the level of locomotion activity (p < 0.01) and increased time spent in the central area after prenatal lead exposure (p < 0.01, Fig. 1b). These findings implied a protective role of omega-3 fatty acid supplementation against lead exposure-induced anxiety in the offspring.
Maternal omega-3 fatty acid supplementation ameliorated prenatal lead exposure induced anxiety in the offspring. Open field test with 3 trails of training was carried out. The total number of circuit breaks was counted as a locomotive behavior and locomotion counts are shown in a. The time spent in the central area was recorded in b. n = 10 for each group. Data are shown with mean ± SD. ##p < 0.01 compared to control, *p < 0.05 compared to PbAc. Two-way ANOVA followed Tukey’s multiple comparisons test.
Prenatal lead exposure could negatively impact mental development in the offspring (Jedrychowski et al., 2009). To evaluate the effects of omega-3 in improving memory and learning, the Morris water maze was carried out on the offspring. No significant change was observed between control animals and control animals treated with omega-3 (Fig. 2a). The escape latency results showed a declining tendency in all four groups. The escape latency in prenatal lead exposure animals was significantly higher than control animals (p < 0.01), whereas treatment with omega-3 significantly reduced the escape latency (p < 0.01, Fig. 2a). Spatial memory was evaluated using a probe trial. Time in target quadrant and the number of platform site crossings in the prenatal lead exposure group were markedly reduced compared to the control group (p < 0.001, respectively, Fig. 2b, c). In contrast, omega-3 significantly increased time in target quadrant and the number of platform site crossings compared to the prenatal lead exposure group (p < 0.01, p < 0.05, respectively, Fig. 2b, c).
Maternal omega-3 fatty acid supplementation ameliorated prenatal lead exposure induced cognitive impairments in the offspring. The Morris water maze testing was carried out. In 4 days of training sessions, the mice’s escape latencies were recorded (a). In the probe trial, the time in the target quadrant in 60 sec (b) and the number of platform site crossings (c) were recorded. n = 10 for each group. Data are shown with mean ± SD. ##p < 0.01, ###p < 0.001 compared to control, *p < 0.05, **p < 0.01 compared to PbAc. Two-way ANOVA followed Tukey’s multiple comparisons test and One-way ANOVA followed Dunn’s multiple comparisons test.
Consistently, cognitive function was further evaluated using the Y-maze and nest-building test. Our results revealed that alternation rate for Y-maze test was significantly reduced after prenatal lead exposure compared with the control group (p < 0.01), which was significantly increased by the treatment with omega-3 (p < 0.05, Fig. 3a). Similarly, scores for nest-building test showed a significant decrease after prenatal lead exposure (p < 0.01), as well as a notable increase when treated with omega-3 (p < 0.05, Fig. 3b). Taken together, these results indicated that omega-3 could reduce cognitive impairment induced by prenatal lead exposure in the offspring.
Maternal omega-3 fatty acid supplementation ameliorated prenatal lead exposure induced cognitive impairments in the offspring. Y-maze test (a) and nest‐building test (b) were conducted. n = 10 for each group. Data are shown with mean ± SD. ##p < 0.01 compared to control, *p < 0.05 compared to PbAc. One-way ANOVA followed Dunn’s multiple comparisons test.
BDNF has been recognized as a crucial mediator in cognitive function through TrkB and cyclic AMP response element binding protein (CREB) (Gomez-Pinilla et al., 2008; Zhou et al., 2018; Motaghinejad et al., 2020). To determine whether omega-3 improved cognitive function in the offspring via the BDNF/TrkB/CREB signaling pathway, we measured the protein and mRNA levels of BDNF, TrkB and CREB using ELISA and qPCR, respectively. The protein levels of BDNF in both the cortex and hippocampus were significantly increased in healthy animals and prenatal lead exposure animals treated with omega-3, when compared to the control group (p < 0.01, respectively, Fig. 4a, b). Interestingly, in the prenatal lead exposure group, the protein levels of BDNF in both the cortex and hippocampus were reduced compared to the healthy animals treated with omega-3. However, there was no statistically significant difference between the control group and prenatal lead exposure group. In parallel, we found that the mRNA levels of BDNF, TrkB and CREB in the prenatal lead exposure group were the same as control group, which were dramatically increased in healthy animals and prenatal lead exposure animals treated with omega-3 (p < 0.01, p < 0.001, p < 0.01, respectively, Fig. 4c–e).
Maternal omega-3 fatty acid supplementation improved the expressions of BDNF, TrkB and CREB in the brain of offspring. The levels of BDNF in the cortex (a) and hippocampus (b) were measured by ELISA. N = 10 for each group. RT-qPCR was used to measure the mRNA levels of BDNF (c), TrkB (d) and (Motaghinejad et al., 2020) (e) in the whole brains. N = 3 for each group. Data are shown with mean ± SD. ##p < 0.01, ###p < 0.001 compared to control, *p < 0.05, **p < 0.01 compared to PbAc. One-way ANOVA followed Dunn’s multiple comparisons test.
Oxidative stress is known to be induced by lead exposure (Murata et al., 2009). Here we measured the levels of oxidative stress marker MDA and anti-oxidants such as SOD, GSH and CAT. MDA, as an indicator of lipid peroxidation, was significantly increased in the prenatal lead exposure group (p < 0.001, Fig. 5a) and reduced by omega-3 treatment compared to control animals (p < 0.01, Fig. 5a). Consistently, the levels of SOD, GSH and CAT were significantly decreased in the prenatal lead exposure group compared to the control (p < 0.05, p < 0.05, p < 0.01, respectively, Fig. 5b–d). In contrast, treatment with omega-3 significantly reduced the levels of SOD, GSH and CAT compared to control (p < 0.001, respectively, Fig. 5b–d). These findings indicated that omega-3 reduced prenatal lead exposure-induced oxidative stress in the offspring.
Maternal omega-3 fatty acid supplementation ameliorated prenatal lead exposure induced oxidative stress in brain of the offspring. Levels of MDA (a), SOD (b), GSH (c) and CAT (d) in the whole brain were measured. N = 10 for each group. Data are shown with mean ± SD. ###p < 0.001 compared to control, **p < 0.01, ***p < 0.001 compared to PbAc. One-way ANOVA followed Dunn’s multiple comparisons test.
In order to determine the signaling pathway responsible for omega-3 in reducing oxidative stress after prenatal lead exposure, we measured protein levels of Nrf2 and HO-1 using Western blot. The protein level of nuclear Nrf2 was significantly reduced in the prenatal lead exposure group (p < 0.05), which was markedly increased by omega-3 supplementation (p < 0.01, Fig. 6a). The same trends were observed in terms of cytoplasmic Nrf2, albeit without statistically significant change (Fig. 6b). The protein level of HO-1 in the prenatal lead exposure group showed no statistically significant change when compared to the control group. Notably, omega-3 treatment significantly increased HO-1 protein expression in both the control and prenatal lead exposure animals (p < 0.01, Fig. 6c). Taken together, these findings suggested that omega-3 improved anti-oxidants levels via upregulating Nrf2 and HO-1 after prenatal lead exposure.
Maternal omega-3 fatty acid supplementation activated Nrf2/HO-1 pathway in brain of the offspring. Protein extracts of offspring mice brain were analyzed by Western blot for Nrf2 protein expressions in the nucleus (a) and cytoplasm (b). Protein extracts of offspring mice brain were analyzed by Western blot for HO-1 in the brain (C). The expressions were normalized to control. N = 3 for each group. Data are shown with mean ± SD. #p < 0.05, ##p < 0.01 and ns in yellow means no significance compared to control. ns in red means no significance compared to control. **p < 0.01 and ns in blue means no significance compared to PbAc. One-way ANOVA followed Dunn’s multiple comparisons test.
Maternal lead exposure is frequently reported to cause brain development defects, cognitive impairment in the offspring, negatively affecting the life quality of families (Antonio-García and Massó-Gonzalez, 2008; Hossain et al., 2016). Discovering and developing an effective strategy to prevent and treat maternal lead exposure-induced brain damage is important to improve clinical outcomes. In the present study, we report that omega-3 plays an essential role in improving neurodevelopment and cognitive function in the offspring after maternal lead exposure.
Maternal lead exposure decreases the cognitive abilities in children. A prospective birth-cohort study of 225 mother-infant pairs in Shanghai from 2010 to 2012 showed that prenatal lead exposure was strongly associated with developmental neurotoxicity in children (Zhou et al., 2017). Similarly, a study showed that maternal exposure to a low level of lead could cause behavioral changes in children, such as social withdrawal, easy frustration and easy distraction (Mendelsohn et al., 1998). Consistent with these findings, we showed that prenatal lead exposure significantly increased anxiety and decreased memory capacity in the offspring. Notably, omega-3 fatty acid significantly reduced prenatal lead exposure-induced anxiety and improved memory capacity after prenatal lead exposure in the offspring.
BDNF is essential for brain function and the ability to recover from brain injury (Wu et al., 2008). BDNF could bind to TrkB to further initiate subsequent signaling cascade, resulting in the phosphorylation of the transcription factor CREB, which could, in turn, regulate BDNF gene expression (Scott Bitner, 2012). The BDNF/TrkB/CREB signaling pathway plays a pivotal role in memory formation. A study showed that prenatal lead exposure markedly decreased BDNF and CREB phosphorylation in the hippocampus, leading to learning and memory deficits (Chen et al., 2019). Omega-3 fatty acid and vitamin 12 combined supplementation during pregnancy was reported to significantly upregulate BDNF, TrkB and CREB in both the hippocampus and cortex in the offspring (Rathod et al., 2015). Our results were in agreement with previous studies: the protein and mRNA levels of BDNF, TrkB and CREB in the prenatal lead exposure group were comparable to the control group, and dramatically upregulated by omega-3 fatty acid as compared to control or prenatal lead exposure group. These findings indicate that omega-3 fatty acid improves cognitive function through upregulating the BDNF/TrkB/CREB signaling pathway during prenatal lead exposure.
Oxidative stress is one of major factors contributing to brain damage during prenatal lead exposure (Hossain et al., 2016). A disrupted anti-oxidant system during prenatal lead exposure results in massive accumulation of reactive oxygen species, leading to cell apoptosis and neurotoxicity (Yu et al., 2021). A previous study showed that maternal aerobic training combined with Cur/CaCO3 supplementations could reduce maternal lead exposure-induced memory dysfunction in the offspring by reducing oxidative stress (Amooei et al., 2021). Lead exposure was reported to inhibit the activities of anti-oxidant enzymes, leading to increased byproduct of lipid peroxidation MDA in the brain (Antonio-García and Massó-Gonzalez, 2008). Importantly, treatment with anti-oxidants significantly reduced MDA by 30–40% with relative to the lead exposure group (Antonio-García and Massó-Gonzalez, 2008). These results indicate that targeting anti-oxidants could serve as a strategy to reduce oxidative stress-induced neurotoxicity during lead exposure. In agreement with these results, we showed that MDA level in the prenatal lead exposure group was significantly increased compared to the control group, which could be reduced by omega-3. Correspondingly, we observed anti-oxidants SOD, GSH and CAT were significantly reduced in the prenatal lead exposure group and restored by the treatment with omega-3 fatty acid. These data suggest that omega-3 fatty acid supplementation plays a strong anti-oxidative role in prenatal lead exposure-induced cognitive impairment in the offspring.
Nrf2, a transcription factor, is responsible for regulating redox balance. NRF2 translocates from the cytoplasm to the nucleus and binds to the antioxidant response element (ARE), subsequently initiating the transcription of anti-oxidative genes (Li et al., 2019; Sandberg et al., 2014). A previous study has demonstrated that targeting Nrf2 could notably improve cognitive function in the offspring after prenatal lead exposure via restoring anti-oxidants, implying a neuroprotective role of Nrf2 in attenuating cognitive impairment induced by lead exposure (Yu et al., 2021). The NRF2/HO-1 pathway plays a critical role in regulating intracellular redox balance. Mechanistically, a study has shown that ERK1/2 activation by ferulic acid facilitates the translocation of Nrf2 from cytosol to nucleus, triggering GCLC and HO-1 transcription (Yu et al., 2021). Moreover, Sakai et al. have shown that omega-3 fatty acid reduced oxidative stress by upregulating Nrf2 expression in vascular endothelial cells (Sakai et al., 2017). In the currently study, we showed that nuclear Nrf2 and HO-1 were significantly restored after omega-3 fatty acid supplementation as compared to the prenatal lead exposure group, strongly implying that omega-3 fatty acid exerts its anti-oxidant role via the Nrf2/HO-1 signaling pathway.
In summary, the current study showed that omega-3 fatty acid supplementation significantly improved memory capacity and cognitive function in the offspring after prenatal lead exposure. Mechanistically, omega-3 fatty acid supplementation effectively upregulated the BDNF/TrkB/CREB signaling pathway in the offspring after prenatal lead exposure. In addition, omega-3 fatty acid supplementation restored anti-oxidants through promoting the Nrf2/HO-1 pathway, thereby reducing cognitive impairment in the offspring after maternal lead exposure.
In conclusion, in the current study, we demonstrate that omega-3 fatty acid could improve cognitive function via upregulating BDNF/TrkB/CREB, as well as reduce oxidative stress by promoting the Nrf2/HO-1 pathway, thereby reducing neurotoxicity and brain dysfunction in the offspring after prenatal lead exposure. We hereby provide in vivo evidence to support that omega-3 fatty acid supplementation could act as an effective approach for preventing and treating prenatal lead exposure-induced brain developmental impairment.
Conflict of interestThe authors declare that there is no conflict of interest.
