Mechanism of cleft palate in C57BL/6N mice induced by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin / 中华口腔医学杂志

Objective: To explore the molecular mechanism of cleft palate in mice induced by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD). Methods: The pregnant mice were randomly divided into TCDD-treated group (n=42) and control group (n=42). TCDD-treated group was given by gavage a single dose of TCDD (64 μg/kg) at 8: 00 AM on gestation day 10 (GD10) and the control group was given by gavage the isopyknic corn oil. At GD13-GD15, the fetal mice palate development was observed by HE staining. The mouse embryonic palatal mesenchymal cell proliferation was detected by 5-bromo-2-deoxyuridine (BrdU) immunofluorescence. The localization and expression of maternally expressed gene3 (MEG3) in mouse embryonic palatal mesenchymal cells was detected by situ hybridization and real-time PCR (RT-PCR). The key protein expressions of transforming growth factor-β (TGF-β)/Smad signaling pathway in mouse embryonic palatal mesenchyme were analyzed by Western blotting. The interaction of MEG3 and TGF-β receptor Ⅰ (TGF-βRⅠ) was examined by RNA binding protein immunoprecipitation (RIP). Results: At GD13 and GD14, compared with the control group, the ratio of BrdU-positive cells in the palatal mesenchyme of TCDD-treated fetuses decreased significantly (GD13, t=6.66, P=0.003; GD14, t=6.56, P=0.003). However, at GD15, the ratio of BrdU-positive cells was significantly increased (t=-5.98, P=0.004). MEG3 was mainly expressed in the nuclei of fetal mouse palatal mesenchymal cells, and the expression of MEG3 in TCDD group was significantly increased at GD13, GD14 and GD15(GD13, t=39.28, P=0.012; GD14, t=18.75, P=0.042; GD15, t=28.36, P=0.045). At GD14, TCDD decreased the levels of p-Smad2 and Smad4 in embryonic palate mesenchymal cells (p-Smad2, t=9.48, P=0.001;Smad4, t=63.10, P=0.001), whereas the expression of Smad7 was significantly increased at GD14 (t=30.77, P<0.001). The results of the RIP experiment showed that the amount of TGF-βRⅠ-bound MEG3 in mouse embryonic palatal mesenchymal cells in the TCDD group (23.940±1.301) was higher than that in the control group (8.537±1.523)(t=24.55, P<0.001). Conclusions: MEG3 is involved in the suppression of mouse embryonic palatal mesenchymal cell proliferation, functioning at least in part via interacting with the TGF-βRⅠ protein and thereby suppressing Smad signaling in the context of TCDD induced cleft palate.

Correlation of serum carnitine levels with age and sex among Chinese adults in Nanjing / 中华男科学杂志

<p><b>OBJECTIVE</b>Carnitine, the only carrier for fatty acid to enter mitochondria for oxidation, has significant effects on serum lipids metabolism and male fertility. This study aimed to investigate the correlation of serum carnitine levels with sex and age among healthy Chinese adults in Nanjing.</p><p><b>METHODS</b>We obtained fasting blood samples from 347 healthy Chinese adults in Nanjing (182 males, 165 females, aged from 20 to 89), determined the levels of serum free, acylcarnitine and total carnitine by high performance liquid chromatography with pre-column ultraviolet derivatization, and analyzed the correlation of serum carnitine levels with the age and sex of the subjects.</p><p><b>RESULTS</b>Total and free carnitine levels were significantly higher in the males than in the females (P < 0.05) while no statistically significant differences were found in the acylcarnitine level (P > 0.05). Among those aged between 20 to 50 years, levels of serum free and total carnitine were significantly higher in men than in women (P < 0.05) and they increased with age in females, but with no significant differences between males and females older than 50 years. The acylcarnitine level showed no obvious differences in any age and sex groups.</p><p><b>CONCLUSION</b>Serum free and total carnitine levels are correlated with sex and age in healthy adults.</p>