Effects and significance of follistatin-like 1 on alveolar epithelial cell differentiation in a congenital diaphragmatic hernia rat model

Abstract

Objective To explore the effects and significance of follistatin-like 1 (FSTL1) on alveolar epithelial cell differentiation in a congenital diaphragmatic hernia (CDH) rat model. Methods Adult specific pathogen-free (SPF) grade Sprague-Dawley (SD) postnatal rats were selected and randomized into two groups of model and blank. Nitrofen was employed for establishing a CDH rat model. Fetal rats were dissected. CDH group was defined as fetal rats with CDH in model group and control group normal fetal rats in blank group. Left lung of fetal rats was harvested for further researches. Lung morphological difference between two groups were compared after hematoxylin-eosin(HE)stain. The expression levels of FSTL1, thyroid transcription factor 1 (TTF1) and aquaporin 5 (AQP5) were examined by immunohistochemistry, Western blot and qRT-PCR. Western blot was utilized for detecting the expression levels of surfactant protein B, surfactant protein C and their protein precursors. All comparisons were conducted with independent t test. Results CDH rat model was successfully established(n=21). Radial alveolar count of fetal rat lungs in CDH group were lower than that in control group(2. 88±0. 19 vs 5. 68±0. 24)(P<0. 001). Immunohistochemistry indicated that FSTL1, TTF1 and AQP5 were expressed in lung tissue and their expression intensities differed between two groups. The mRNA and protein expression of FSTL1 in CDH group (0. 555 0±0. 046 2 vs 0. 694 9±0. 025 0) were less than those of control group (1. 009 2±0. 163 6 vs 1. 006 2±0. 106 7) and the differences were statistically significant (P<0. 05). The mRNA and protein expression of AQP5 in CDH group (0. 552 4±0. 147 4 vs 0. 489 2±0. 140 7) was lower than those of control group (1. 010 3±0. 182 2 vs 0. 835 2±0. 114 9) and there were statistically significant inter-group differences (P<0. 05). Whereas, the mRNA and protein expression of TTF1 in CDH group (2. 807 3±0. 571 0 vs 0. 738 9±0. 066 0) was higher than that of control group (1. 017 2±0. 222 5 vs 0. 327 8±0. 035 3). These differences were statistically significant. Furthermore, the protein expressions of protein precursors, "Pro-SP-B and Pro-SP-C", were significantly higher in CDH group (1. 157 0±0. 135 4 vs 0. 958 8±0. 024 9) than control group (0. 911 3±0. 034 9 vs 0. 499 9±0. 067 2). In contrast, the protein expressions of SP-B and SP-C (0. 458 7±0. 026 4 vs 0. 134 4±0. 065 8)were lower in CDH group than those in control group(0. 711 2±0. 066 8 vs 0. 329 6±0. 029 6). The differences were statistically significant (P<0. 05). ConclusionsFSTL1 may contribute to lung dysplasia in CDH through its impact on alveolar epithelial cell differentiation and surfactant protein maturation.