Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Brain Behav. 2024 Sep;14(9):e70040. doi: 10.1002/brb3.70040.
Children in low socioeconomic status (SES) communities are at higher risk of exposure to lead (Pb) and potentially more severe adverse outcomes from Pb exposures. While the factors encompassing SES are complex, low SES households often have less enriching home environments and parent-child interactions. This study investigated the extent to which environmental/behavioral factors (quality of maternal care and richness of the postnatal environment) may modify adverse effects from Pb exposure.
Long-Evans female rats were randomly assigned to Control (no Pb), Early Postnatal (EPN: birth through weaning), or Perinatal (PERI: 14 days pre-mating through weaning) Pb exposure groups. From postnatal days (PNDs) 2-9, maternal care behaviors were observed, and dams were classified as low or high maternal care based on amounts of licking/grooming and arched back nursing. At weaning, pups were randomly assigned to enriched or non-enriched environments. At PND 55, animals began trace fear conditioning and associative memory was tested on days 1, 2, and 10 postconditioning.
Control offspring showed no significant effects of maternal care or enrichment on task performance. Females with EPN-Pb exposure and males with PERI-Pb exposure living in the non-enriched environment and having an LMC mother had significant memory impairments at days 2 and 10 that were not observed in comparably housed animals with HMC mothers. Enriched animals had no deficits, regardless of maternal care status.
These results show the potential for modulatory influences of maternal care and housing environment on protecting against or reversing at least one aspect of Pb-induced cognitive/behavioral dysfunction.
社会经济地位（SES）较低社区的儿童接触铅（Pb）的风险更高，并且可能因 Pb 暴露而产生更严重的不良后果。虽然 SES 所包含的因素很复杂，但低收入家庭的环境往往不够丰富，亲子互动也较少。本研究调查了环境/行为因素（母婴护理质量和产后环境丰富度）在多大程度上可能改变 Pb 暴露的不良影响。
将长耳雌性大鼠随机分配到对照组（无 Pb）、早期产后（EPN：出生至断奶）或围产期（PERI：交配前 14 天至断奶）Pb 暴露组。从出生后第 2-9 天，观察母婴护理行为，并根据舔舐/梳理和拱形背部护理的次数将母体分为低或高母婴护理。在断奶时，幼崽被随机分配到丰富或非丰富的环境中。在 PND55，动物开始进行痕迹恐惧条件反射，在条件反射后第 1、2 和 10 天测试联想记忆。
对照组后代的母婴护理或丰富度对任务表现没有显著影响。在非丰富环境中生活且具有 LMC 母亲的 EPN-Pb 暴露的雌性和 PERI-Pb 暴露的雄性在第 2 和第 10 天的记忆受损，而在具有 HMC 母亲的可比动物中没有观察到这种记忆受损。无论母婴护理状态如何，丰富的动物都没有缺陷。
这些结果表明，母婴护理和住房环境的调节影响有可能预防或逆转至少 Pb 诱导的认知/行为功能障碍的一个方面。
