Sub-optimal paternal diet at the time of mating perturbs maternal adaptations in the late gestation mouse. Sub-optimal paternal diet at the time of mating perturbs maternal adaptations in the late gestation mouse

Pregnancy represents a stage during which maternal physiology and homeostatic regulation undergo dramatic change and adaptation. The fundamental purpose of these adaptations is to ensure the survival of her offspring through adequate nutrient provision and an environment that is tolerant to the semi-allogenic fetus. While poor maternal diet during pregnancy is associated with perturbed maternal adaptations during pregnancy, the influence of paternal diet on maternal well-being is less clearly-defined. We fed male mice either a control (CD), low protein diet (LPD), a high fat/sugar Western diet (WD) or the LPD or WD supplemented with methyl donors (MD-LPD and MD-WD respectively) for a minimum of 8 weeks prior to mating. Females were culled at day 17 of gestation for the analysis of maternal metabolic, gut, cardiac and bone health. Paternal diet had minimal influences on maternal metabolic status or gut microbiota diversity. However, analysis of the maternal hepatic transcriptome revealed distinct profiles of differential gene expression in response to the diet of the father. Paternal LPD and MD-LPD resulted in differential expression of genes associated with lipid metabolism, transcription, ubiquitin conjugation and immunity in dams, while paternal WD and MD-WD modified the expression of genes associated with ubiquitin conjugation and cardiac morphology. Finally, we observed changes in maternal femur length, volume of trabecular bone, trabecular connectivity, volume of the cortical medullar cavity and thickness of the cortical bone in response to the father’s diets. Our current study demonstrates that poor paternal diet at the time of mating can influence the patterns of maternal metabolism and gestation-associated adaptations to her physiology. Such changes could have significant consequences for the long-term health of his offspring and the mother. Overall design: To investigate pregnant murine liver RNA profile changes in response to matings with sub-optimal diet fed fathers. We fed male mice either control diet (NPD; 18% casein, 21% sugar, 0% milk fat, 0% cholesterol), isocaloric low protein diet (LPD; 9% casein, 24% sugar, 0% milk fat, 0% cholesterol), ‘Western’ diet (WD; 19% casein, 34% sugar, 20% milk fat, 0.15% cholesterol) or LPD or WD supplemented with methyl-donors [an addition of 5 g/kg diet choline chloride, 15 g/kg diet betaine, 7.5 g/kg diet methionine, 15 mg/kg diet folic acid, 1.5 mg/kg diet vitamin B12 to either LPD (MDL) or WD (MDWD)] for a minimum of 8 weeks before males were mated with standard chow fed females. At gestational day 17.5 females were euthanised and liver samples collected for RNA sequencing.

妊娠是一段母体生理与稳态调节发生剧烈变化与适应性重塑的阶段。此类适应性改变的核心目的在于通过充足的营养供给与耐受半同种异体胎儿的内环境，保障子代存活。尽管妊娠期母体不良饮食与孕期母体适应性紊乱密切相关，但父代饮食对母体健康的影响尚不明晰。

本研究将雄性小鼠分为四组，分别饲喂正常对照日粮（control diet, CD）、低蛋白日粮（low protein diet, LPD）、高糖高脂西式日粮（high fat/sugar Western diet, WD），以及分别添加甲基供体（methyl donors, MD）的低蛋白日粮（MD-LPD）与西式日粮（MD-WD），于交配前至少饲喂8周。于妊娠第17天处死雌性小鼠，分析其代谢、肠道、心脏与骨骼健康状况。

父代饮食对母体代谢状态或肠道菌群（gut microbiota）多样性的影响极小。但对母体肝脏转录组（hepatic transcriptome）的分析显示，父代不同日粮可诱导母体产生差异显著的基因表达谱。父代饲喂LPD与MD-LPD可导致母鼠体内与脂质代谢、转录、泛素结合以及免疫相关的基因出现差异表达；而父代饲喂WD与MD-WD则改变了母鼠体内与泛素结合及心脏形态相关的基因表达。最终，我们观察到父代饮食可影响母体股骨长度、骨小梁体积、骨小梁连接性、皮质髓腔体积以及皮质骨厚度。

本研究证实，交配前父代的不良饮食可改变母体代谢模式及妊娠相关生理适应性改变，此类改变可能对子代与母体的长期健康产生重要影响。

实验整体设计：为探究与饲喂次优日粮的雄性小鼠交配后，孕鼠肝脏RNA表达谱的变化。我们将雄性小鼠分为四组，分别饲喂对照日粮（NPD, control diet；含18%酪蛋白、21%蔗糖、0%乳脂、0%胆固醇）、等热量低蛋白日粮（LPD, low protein diet；含9%酪蛋白、24%蔗糖、0%乳脂、0%胆固醇）、‘西式’日粮（WD, Western diet；含19%酪蛋白、34%蔗糖、20%乳脂、0.15%胆固醇），以及分别添加甲基供体的LPD与WD日粮[向LPD（MDL）或WD（MDWD）中添加5 g/kg日粮氯化胆碱、15 g/kg日粮甜菜碱、7.5 g/kg日粮蛋氨酸、15 mg/kg日粮叶酸、1.5 mg/kg日粮维生素B12]，于交配前至少饲喂8周，随后与饲喂标准颗粒日粮的雌性小鼠交配。于妊娠第17.5天处死雌性小鼠，采集肝脏样本进行RNA测序（RNA Sequencing）。