Effects of early-life exposure to angiotensinⅡ type 1 receptor autoantibody on lipid metabolism in offspring rats / 中华围产医学杂志

ABSTRACT

Objective:To investigate the effects of early-life (intrauterine and breastfeeding period) exposure to angiotensin Ⅱ type 1 receptor autoantibody (AT 1-AA) on lipid metabolism in offspring rats. Methods:Thirty-two AT 1-AA negative healthy nonpregnant specific pathogen free female Sprague Dawley rats weighing 150-170 g were randomly divided into two groups. Those in the immune group ( n=16) were subcutaneously injected with the mixture of an equal volume of Freund's adjuvant and the second extracellular loop of human-derived angiotensin Ⅱ receptor type 1 (AT1R-ECⅡ) repeatedly to establish the AT 1-AA-positive rat model by active immunization and those in the control group ( n=16) with normal saline solution. Before each immunization, blood samples were collected from the tail of rats to detect serum AT 1-AA levels of those rats in both groups, and the AT 1-AA-positive rat model was successfully established when the serum AT 1-AA was positive and its level reached a plateau. After eight weeks of immunization, the female rats in the two groups were mated with healthy AT 1-AA-negative male rats to conceive. Serum samples were collected from the maternal and offspring rats at the gestation of 18 days (G18), postnatal 21 days (P21), and from the normally fed offspring rats from the time of weaning to 12 weeks old (W12). Active immunization was not performed on the offspring throughout the experiment. The serum AT 1-AA levels of maternal and offspring rats were determined by enzyme-linked immunosorbent assay, and serum AT1-AA was positive when the ratio of AT1-AA level of the immune group over the control group ≥2.1. The blood lipid levels of maternal and offspring rats were measured by an automatic biochemical analyzer. Serum AT 1-AA levels, total cholesterol (TC), high-density lipoprotein-cholesterol [instead of high-density lipoprotein (HDL)], low-density lipoprotein-cholesterol, and free fatty acid levels of the offspring and maternal rats were determined for correlation analysis. Two independent sample t-test, linear regression analysis, and analysis of variance were adopted for statistical analysis. Results:(1) The serum levels of AT 1-AA in maternal rats at G18 and P21 in the immune group were significantly higher than those in the control group (G18: 1.170±0.190 vs 0.114±0.016, t=14.64; P21: 0.988±0.283 vs 0.084±0.006, t=9.57; both P<0.001). (2) The serum levels of AT 1-AA in the offspring at G18 and P21 in the immune group were significantly higher than those in the control group (offspring at G18: 0.948±0.220 vs 0.105±0.010, t=10.10; male offspring at P21: 0.758±0.273 vs 0.080±0.002, t=7.46; female offspring at P21: 0.774±0.274 vs 0.084±0.005, t=7.55; all P<0.001), which showed a positive correlation with those in maternal rats at the same period (offspring at G18: R=0.78; male offspring at P21: R=0.82; female offspring at P21: R=0.82; all P<0.05). However, there was no significant difference in the serum AT 1-AA level in offspring at W12 between the immune and control group ( P>0.05). (3) The serum levels of TC at G18 and P21, and HDL at P21 in maternal rats in the immune group were all higher than those in the control group [TC at G18: (2.36±0.32) vs (1.95±0.24) mmol/L, t=2.70; P21: (2.82±0.50) vs (2.18±0.26) mmol/L, t=3.41; HDL at P21: (1.94±0.33) vs (1.57±0.23) mmol/L, t=2.80; all P<0.05]. (4) Compared with the offspring in the control group, there was no significant change in lipid metabolism at G18 and W12 in the offspring in the immune group (both P>0.05). The serum levels of TC and HDL in male and female offspring at P21 in the immune group were higher than their counterparts in the control[TC in male offspring: (2.38±0.52) vs (1.83±0.30) mmol/L, t=2.73; HDL in male offspring: (1.44±0.32) vs (1.07±0.18) mmol/L, t=2.98; TC in female offspring: (2.50±0.72) vs (1.70±0.26) mmol/L, t=3.16; HDL in female offspring: (1.41±0.33) vs (1.00±0.14) mmol/L, t=3.41; all P<0.05]. (5) The serum levels of TC and HDL in male and female offspring at P21 in the immune group showed no correlation with those in maternal rats at P21 (all R<0.5, all P>0.05). The serum levels of HDL in male and female offspring at P21 in the immune group had a positive correlation with their own serum TC levels (male offspring: R=0.98; female offspring: R=0.97; both P<0.001) and also with their own serum AT 1-AA levels (male offspring: R=0.74, P=0.023; female offspring: R=0.91, P=0.001). The serum levels of TC in male and female offspring at P21 in the immune group had a positive correlation with their serum AT 1-AA levels (male offspring: R=0.72, P=0.030; female offspring: R=0.90, P=0.001). Conclusion:The early-life exposure to AT 1-AA may cause abnormal expression of TC and HDL in offspring rats.