Prenatal dexamethasone exposure induces chondrodysplasia in offspring fetal female rats and its underlying mechanism
10.3867/j.issn.1000-3002.2019.01.008
- Author:
Wei LI
1
Author Information
1. Department of Orthopedic Surgery, Zhongnan Hospital
- Publication Type:Journal Article
- Keywords:
Dexamethasone;
Dyschondroplasia;
Glycosyltransferase;
Insulin-like growth factor-1
- From:
Chinese Journal of Pharmacology and Toxicology
2019;33(1):54-62
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE To investigate the effect of prenatal dexamethasone exposure (PDE) on chondrogenesis of female fetal rats and those of dexamethasone treatment on gene expression of chondrocytes, and to explore the underlying mechanism. METHODS ?In vivo, Wistar female ratswere conceived naturally, and the PDE group was sc given dexamethasone 0.2 mg-kg"1 once a day for 9-20 d after gestation (GD9-20). Pregnant rats were sacrificed on GD20( and cartilage samples of female fetal rats were collected. Tho morphology of cartilege was observed by HE and saffranin O staining. The expressions of aggrecan, O-xylosyltransfefase I (XylT-1), pi, 3-glucuronosyl transferase I [GlcAT-1).,4-galactosyttransterase 7, (GalT-I), insulin-like growth factor-1 (IGF-1), IGF-1 receptor (IGF-1R). protein kinase B {AKT) and activator protein I (AP-1) mRNA in cartilage tissues were examined by realtime quantitative PCR (RT-PCR). The expressions of XylT-I . GlcAT-I . GalT-I . IGF-1. AKT and AP-1 were detected by immunohistochemistry. In vitro, GD20 Wistar female fetal rats were used to extract chondrocytes from fetal knee joints. Dexamethasone (100 and 500 nmol-L"'). IGF-1 (100 ug-L"'). IGF-1 R inhibitor NVP-AEW541 (1 umol-L"), AKT inhibitor MK-2206 (1 pmol-L") and AP-1 inhibitor SR-11302 (1 umol-L∗') were treated for 24 h. The content of glycosaminoglycan (GAG) in the cefl supeRNAtant was detected by DMB staining. The expressions of XylT-1 , GlcAT-1 , GalT-1 , IGF-1 R, AKT and AP-1 mRNA were detected by RT-PCR. The expressions of XylT-I , GlcAT-I and GalT-I protein were detected by Western blotting. RESULTS (J) In vivo the results of HE and saffranin O staining showed that the number of articular chondrocytes of female fetal rats in PDE group was reduced, the arrangement of surface chondrocytes was disorderty. and staining of cartilage matrix became kghter and uneven. The protein and mRNA expression of cartilage, XylT-I , GlcAT-I , GalT-I and proteins related to IGF-1/AKT/AP-1 pathway were reduced in PDE group compared with normal control group (P<0.05, P<0.01). @ In vitro compared with the normal control group, the contcnt of GAG in the supeRNAtant of chondrocytes of female fetal rats was decreased (P<0.05). and the mRNA expressions of XylT-I , GlcAT-I, GalT-I and proteins related with IGF-1/AKT/AP-1 pathways were deceased (P<0.05). Compared with the dexamethasone 500 nmol-L"1 group, IGF-1 100 pg∗L" increased the mRNA expression levels of the above proteins {P<0.05, P<0.01). Compared with the normal control group, the protein and mRNA expressions of XytT-I , GlcAT-I and GalT-| in IGF-1 treatment group were increased, while those in IGF-1R/AKT/AP-1 inhibitor treatment groups were decreased (P<0.05, F<0.01). Compared with the SR-11302 group, there was no significant change in the protein and mRNA expression levete of XylT-I, GlcAT-1 and GalT-I after co-treatment with IGF-1. CONCLUSION PDE induceds chondrodysplasia in female fetal rats, which is related to the insufficiency of cartilage matrix synthesis induced by decreasing expression of glycosyltransferases mediated by low basic activity of IGF-1/AKT/AP-1 pathway.
