Abstract：
OBJECTIVE: To investigate the effects of excessive light exposure during gestation on intrauterine development and early growth of neonates in rats.
METHODS: Pregnant rats were randomly allocated to three groups: the constant light exposure group, non-light exposure group and control group. Blood samples were collected from the tail vein to analyze melatonin and cortisol levels. Weight, daily food and water consumption were recorded. Uterine weight, placental weight and placental diameter were measured on gestational day 19. Natural birth and neonate growth were also monitored. The expression of NR1D1(nuclear receptor subfamily 1 group D member 1) in offspring\'s SCN (suprachiasmatic nuclei), liver and adipose tissue was measured. Expression of NR1D1, MT1(melatonin 1 A receptor) and 11β-HSD2 (placental 11β-hydroxysteroid dehydrogenase type 2) in placenta was also measured. Finally, the expression of MT1 and 11β-HSD2 in NR1D1 siRNA transfected JEG-3 cells was evaluated.
RESULTS: There were no significant differences in maternal weight gain, pregnancy duration, uterine weight, placental body weight, placental diameter, fetal number among three groups. There were no significant differences in weights or lengths of offspring at birth. Compared to other two groups, constant light exposure group showed significantly more rapid growth of offspring in 21st day post-birth. The expression of NR1D1 in SCN, liver and adipose tissues of offspring was not significantly different among three groups. The maternal serum melatonin and cortisol levels of the constant light exposure group were lower and higher than other two groups, respectively. The expressions of NR1D1, MT1 and 11β-HSD2 were all decreased in placenta of the constant light exposure group. The expression of MT1 and 11β-HSD2 in JEG-3 cells were decreased after NR1D1 siRNA transfection.
CONCLUSIONS: Excessive light exposure during pregnancy results in elevated cortisol and reduced melatonin exposure to fetuses in uterus, potentially contributing to an accelerated early growth of offspring in rats.
METHODS: Pregnant rats were randomly allocated to three groups: the constant light exposure group, non-light exposure group and control group. Blood samples were collected from the tail vein to analyze melatonin and cortisol levels. Weight, daily food and water consumption were recorded. Uterine weight, placental weight and placental diameter were measured on gestational day 19. Natural birth and neonate growth were also monitored. The expression of NR1D1(nuclear receptor subfamily 1 group D member 1) in offspring\'s SCN (suprachiasmatic nuclei), liver and adipose tissue was measured. Expression of NR1D1, MT1(melatonin 1 A receptor) and 11β-HSD2 (placental 11β-hydroxysteroid dehydrogenase type 2) in placenta was also measured. Finally, the expression of MT1 and 11β-HSD2 in NR1D1 siRNA transfected JEG-3 cells was evaluated.
RESULTS: There were no significant differences in maternal weight gain, pregnancy duration, uterine weight, placental body weight, placental diameter, fetal number among three groups. There were no significant differences in weights or lengths of offspring at birth. Compared to other two groups, constant light exposure group showed significantly more rapid growth of offspring in 21st day post-birth. The expression of NR1D1 in SCN, liver and adipose tissues of offspring was not significantly different among three groups. The maternal serum melatonin and cortisol levels of the constant light exposure group were lower and higher than other two groups, respectively. The expressions of NR1D1, MT1 and 11β-HSD2 were all decreased in placenta of the constant light exposure group. The expression of MT1 and 11β-HSD2 in JEG-3 cells were decreased after NR1D1 siRNA transfection.
CONCLUSIONS: Excessive light exposure during pregnancy results in elevated cortisol and reduced melatonin exposure to fetuses in uterus, potentially contributing to an accelerated early growth of offspring in rats.
摘要：
目的：探讨妊娠期过度光照对大鼠宫内发育及新生儿早期生长的影响。
方法：妊娠大鼠随机分为三组：持续光照组，非光照组和对照组。从尾静脉收集血样以分析褪黑激素和皮质醇水平。重量,记录每日食物和水的消耗量.子宫重量,在妊娠第19天测量胎盘重量和胎盘直径。还监测了自然出生和新生儿生长。NR1D1（核受体亚家族1组D成员1）在子代SCN（视交叉上核）中的表达，测量肝脏和脂肪组织。还测量了NR1D1，MT1（褪黑激素1A受体）和11β-HSD2（胎盘11β-羟基类固醇脱氢酶2型）在胎盘中的表达。最后,在NR1D1siRNA转染的JEG-3细胞中评估MT1和11β-HSD2的表达。
结果：孕妇体重增加无显著差异，妊娠持续时间,子宫重量,胎盘体重,胎盘直径，三组胎儿数。出生时后代的体重或长度没有显着差异。与其他两组相比，持续光照组的后代在出生后第21天的生长速度明显更快。NR1D1在SCN中的表达,后代的肝脏和脂肪组织在三组之间没有显着差异。常光照射组的母体血清褪黑素和皮质醇水平低于和高于其他两组,分别。持续光照组胎盘组织中NR1D1、MT1和11β-HSD2的表达均降低。NR1D1siRNA转染后，JEG-3细胞中MT1和11β-HSD2的表达降低。
结论：怀孕期间过度的光照会导致皮质醇升高和褪黑激素对子宫胎儿的暴露减少，可能有助于加速大鼠后代的早期生长。
方法：妊娠大鼠随机分为三组：持续光照组，非光照组和对照组。从尾静脉收集血样以分析褪黑激素和皮质醇水平。重量,记录每日食物和水的消耗量.子宫重量,在妊娠第19天测量胎盘重量和胎盘直径。还监测了自然出生和新生儿生长。NR1D1（核受体亚家族1组D成员1）在子代SCN（视交叉上核）中的表达，测量肝脏和脂肪组织。还测量了NR1D1，MT1（褪黑激素1A受体）和11β-HSD2（胎盘11β-羟基类固醇脱氢酶2型）在胎盘中的表达。最后,在NR1D1siRNA转染的JEG-3细胞中评估MT1和11β-HSD2的表达。
结果：孕妇体重增加无显著差异，妊娠持续时间,子宫重量,胎盘体重,胎盘直径，三组胎儿数。出生时后代的体重或长度没有显着差异。与其他两组相比，持续光照组的后代在出生后第21天的生长速度明显更快。NR1D1在SCN中的表达,后代的肝脏和脂肪组织在三组之间没有显着差异。常光照射组的母体血清褪黑素和皮质醇水平低于和高于其他两组,分别。持续光照组胎盘组织中NR1D1、MT1和11β-HSD2的表达均降低。NR1D1siRNA转染后，JEG-3细胞中MT1和11β-HSD2的表达降低。
结论：怀孕期间过度的光照会导致皮质醇升高和褪黑激素对子宫胎儿的暴露减少，可能有助于加速大鼠后代的早期生长。
