The effect of maternal hypercholesterolemia on the placenta and fetal arteries in rabbits / Efeito da hipercolesterolemia maternal sobre a placenta e as artérias fetais em coelhos

ABSTRACT

PURPOSE: To investigate the degree of placental permeability in dyslipidemic rabbits and the consequent vascular dysfunction in fetuses of female rabbits with high lipoprotein levels. METHODS: Fifteen adult females New Zealand White rabbits were divided into two groups. Group 1(n=5) - hypercholesterolemic diet with 0.5 percent cholesterol, and Group 2 (n=10) - control. On day 30, the levels of plasma lipoproteins and triglycerides were analyzed in the mothers, and the presence of collagen was analyzed in the placenta as well as in fetal coronary and aorta. Statistical analyses used the Student's t and the Mann-Whitney tests. RESULTS: Lipoprotein levels were significantly different (p=0.02 to p<0.001) in experimental and control groups. In the hypercholesterolemic group, total cholesterol levels were in average 793mg/dl; triglycerides were in average 257mg/dl; HDL-C was 48mg/dl, and LDL-C was in average 692mg/dl. The amount of collagen per micrometers square (mµ²) in samples from hypercholesterolemic animals was significantly higher than in the control group. CONCLUSIONS: The study confirmed placental permeability to lipoproteins, shown by increased amounts of collagen in fetal tissues. This alteration results in increased susceptibility to atherosclerosis in adult life, representing a risk factor for the early development of disease, which may appear even in the prenatal period.

RESUMO

OBJETIVO: Investigar a permeabilidade placentária em coelhos adultos fêmeas dislipidêmicas e a consequente disfunção vascular em seus fetos. MÉTODOS: Quinze coelhos adultos fêmeas Nova Zelândia Brancas foram distribuídas em grupo dislipidêmico e grupo controle. No trigésimo dia de gestação foram medidos os triglicerídeos e as lipoproteínas nas coelhas e verificada a presença de colágeno na placenta e coronárias fetais. Análise estatística foi feita com teste t de Student´s e Mann-Whitney. RESULTADOS: Os níveis de lipoproteínas foram diferentes estatisticamente entre os grupos (p=0,02 a p<0,001). A quantidade de colágeno por micrômetro quadrado foi significantemente maior no grupo hipercolesterolêmico em comparação ao grupo controle. CONCLUSÕES: O estudo confirmou a permeabilidade placentária para lipoproteínas demonstrando aumento de colágeno nos tecidos fetais. Esta alteração induz ao aumento da suscetibilidade para aterosclerose na vida adulta, representando um fator de risco para desenvolvimento precoce da doença aterosclerótica a qual pode estar presente mesmo no período pré-natal.