Intermittent heat exposure induces thoracic aorta injury in spontaneously hypertensive rats by activating the AMPK/mTOR/ULK1 pathway / 南方医科大学学报

OBJECTIVE@#To investigate the effects of different manners of heat exposure on thoracic aorta injury in spontaneously hypertensive rats (SHRs) and explore the underlying mechanism.@*METHODS@#Normal 6 to 7-week-old male SHRs were randomized into control group (cage at room temperature), intermittent heat exposure group (SHR-8 group, exposed to 32 ℃ for 8 h daily for 7 days) and SHR-24 group (with continuous exposure to 32 ℃ for 7 days). After the treatments, the pathologies of the thoracic aorta of the rats were observed with HE staining, and the expressions of Beclin1, LC3B and p62 were detected with Western blotting and immunofluorescence assay; TUNEL staining was used to observe cell apoptosis in the thoracic aorta, and the expressions of caspase-3, Bax, and Bcl-2 were detected using Western blotting. The effects of intraperitoneal injections of 3-MA (an autophagy agonist), rapamycin (an autophagy inhibitor) or compound C 30 min before intermittent heat exposure on the expressions of proteins associated with autophagy, apoptosis and the AMPK/mTOR/ULK1 pathway in the aorta were examined with immunohistochemistry.@*RESULTS@#In SHR-8 group, the rats showed incomplete aortic intima with disordered cell distribution and significantly increased expressions of Beclin1, LC3II/LC3I and Bax, lowered expressions of p62 and Bcl-2, and increased apoptotic cells in the thoracic aorta (P < 0.05). Pretreatment with 3-MA obviously inhibited the expressions of autophagy- and apoptosis-related proteins, whereas rapamycin promoted their expressions. Compared with the control group, the rats in SHR-8 group had significantly down-regulated p-mTOR and up-regulated p-AMPK and p-ULK1 expression of in the aorta; Treatment with compound C obviously lowered the expressions of p-AMPK and p-ULK1 and those of LC3B and Beclin1 as well.@*CONCLUSION@#In SHRs, intermittent heat exposure causes significant pathologies and promotes autophagy and apoptosis in the thoracic aorta possibly by activating the AMPK/mTOR/ULK1 pathway.

Effects of heat exposure during fixed time on thoracic aorta contractility in rats / 第二军医大学学报

Objective To investigate the effect of heat exposure during fixed time onthe thoracic aorta contractile properties of rats and the related mechanism. Methods Male Wistar rats were randomly divided into control group, random¬time heat exposure group and fixed-time heat exposure group (ambient temperature to 24°C; the two heat exposure groups were exposed to heat [36°C] 6 h daily). After 7 days of heat exposure, the body core temperature of rats was measured by telemetry technology. The response of isolated thoracic aorta to noradrenaline (NA) was determined by organ bath system. Expression of aorta eNOS mRNA and plasma NOx (NO2- and NO3-) content were also examined. Results Heat exposureshowed no significant effects on body core temperature of rats (P>0. 05). Compared with control group, the fixed-time heat exposure group had significantly lowered thoracic aortic vascular reactivity to NA (P<0. 01). Compared with control group and random¬time heat exposed group, the fixed-time heat exposure group had significantly increased eNOS mRNA expression and plasma NOx content (P<0. 05). Conclusion Fixed-time exposure to heat can change the reactivity of the thoracic aorta in rats, and vascular endothelial cell-derived NOS pathway may be involved in the vasodilatory effects.

Prenatal diagnosis of β-thalassaemia using cell-free fetal DNA in maternal plasma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the clinical feasibility of cell-free fetal DNA (cffDNA)-based noninvasive prenatal diagnosis of β-thalassemia.</p><p><b>METHODS</b>Nine samples of amniotic fluid were obtained to detect the 8 common and 9 relatively rare mutation sites of β-thalassaemia in Guangdong Province. The maternal blood samples were also collected for extracting and purification of the cffDNA, and a duplex PCR was performed using 3 pairs of primers and the fetal β-globin genotype was analyzed by reverse dot-blot hybridization.</p><p><b>RESULTS</b>Among the 9 cases, 5 showed fetal genotypes of β-thalassemia inherited from the father by examination of the amniotic fluid, and 2 fetuses were identified to have β-thalassemia genes inherited from the father determined based on the cffDNA in the maternal blood.</p><p><b>CONCLUSIONS</b>The cffDNA-based noninvasive prenatal diagnosis is feasible for β-thalassemia, but the contamination of the maternal background DNA results in a low detection rate.</p>

Screening and identification of auto-antigen RHDAG1 of rheumatic heart disease / 南方医科大学学报

<p><b>OBJECTIVE</b>To identify the candidate auto-antigen of rheumatic heart disease as a molecular marker for this disease.</p><p><b>METHODS</b>The total RNA of the heart tissue of patients with rheumatic heart disease was extracted and reverse-transcribed into long cDNA to construct the phage expression library. The library was screened using the serum from patients with active rheumatic fever, and the positive clone was identified and analyzed by bioinformatics and expressed in vitro. The expressed products were evaluated with Western blotting and its cross-reactivity was assessed.</p><p><b>RESULTS</b>The phage expression library of the heart tissue of patients with rheumatic heart disease was constructed, with the titer of the primary library of 3.3×10(6) pfu/ml, recombinant rate of 99%, and 81% of the inserted segments were larger than 1 kb. An auto-antigen RHDAG1 was identified by screening, which was homologous to keratin 18. RHDAG1 was detected in the serum of patients with active rheumatic fever and of those with rheumatic heart disease, but not in the serum of healthy subjects.</p><p><b>CONCLUSION</b>Phage display library can be an effective strategy to screen the auto-antigens of rheumatic heart disease. The auto-antigen RHDAG1 can be a candidate molecular biomarker of rheumatic heart disease and/or rheumatic fever.</p>