Influence of hypoxia during different pregnancy stages on myocardial remodeling in adult offspring rats / 中华围产医学杂志

ABSTRACT

Objective To evaluate whether the timing of maternal hypoxia during pregnancy could myocardial remodeling in adult offspring.Methods Twenty-four pregnant rats were assigned to the maternal hypoxia group starting from the early period of pregnancy (G1,day 3 to 21 of pregnancy),the group starting from the middle period of pregnancy (G2,day 9 to 21 of pregnancy),the group starting from the late period of pregnancy (G3,day 15 to 21 of pregnancy),or the control group (G0).Six rats were included in each group.Rats in the maternal hypoxia groups (G1,G2 and G3) were subjected to hypoxia for 3 hours in a low pressure cabin with an oxygen concentration of (10± 1) ％.Systolic blood pressure,wet weight of the left ventricle normalized for body weight (left ventricular weight/body weight,LVW/BW),diameter of cardiomyocytes,and the expression levels of collagen Ⅰ and collagen Ⅲ were measured in adult male offspring at the age of 3 and 5 months.One-way ANOVA and SNK test were used for statistical analysis.Results Maternal hypoxia from day 3 to 21 of pregnancy induced higher systolic blood pressure in male offspring at the age of 3 months and 5 months [3 monthsG1 (122.0± 11.7) mmHg,G0 (108.3±9.5) mmHg,F=2.97; 5 monthsG1 (128.5±7.9) mmHg,G0 (114.6±-10.0) mmHg,F=3.17,both P＜0.05].Maternal hypoxia also led to a higher LVW/BW ratio (G1 1.99±0.03,G0 1.80±0.02,P＜0.05),and increased collagen Ⅰ and collagen Ⅲ expression (collagen Ⅰ /β-actinG1 1.76±0.07,G0 0.48±0.04,P＜0.01; collagen Ⅲ /β-actinG1 0.68±0.05,G0 0.34±0.03,P＜0.01) in adult male offspring at the age of 5 months.Maternal hypoxia from day 9 to 21 of pregnancy induced a higher LVW/BW ratio (3 monthsG2 2.15 ± 0.05,G0 1.98 ± 0.02,P＜0.05; 5 monthsG2 1.96±±0.05,G0 1.80±0.02,P＜0.05),and increased collagen Ⅰ and collagen Ⅲ expression (3 monthscollagen Ⅰ /β-actin G2 0.98±±0.02,G0 0.87±0.02,P＜0.05; collagen Ⅲ /β-actinG2 0.87±±0.01,G0 0.82±0.01,P＜0.05; 5 months; collagen Ⅰ /β-actin G2 1.61±0.05,G0 0.48±0.04,P＜0.01; collagen Ⅲ / β-actinG2 0.61 ±0.04,G0 0.34±0.03,P＜0.01) in male offspring at the age of 3 months and 5 months,but did not affect systolic blood pressure.Maternal hypoxia from day 15 to 2l did not have any effect.The diameter of cardiomyocytes in male offspring was not significantly different between the groups.Conclusions Maternal hypoxia during different periods of pregnancy has different effects on cardiac structure in adult rat offspring.Maternal hypoxia started in early or mid-pregnancy leads to cardiac collagen deposition without an increase in myocyte size in adult offspring,which may be independent of the change in blood pressure.