Exploring the Mechanism of Swertia mussotii Franch. for Hepatoprotective Effects with iTRAQ LC-MS/MS.

BACKGROUND AND OBJECTIVE: A Tibetan traditional herb named Swertia mussotii Franch., also called "Zangyinchen" by the local people of the Qinghai-Tibet area, has been used to protect the liver from injury for many years. However, the curative effect and molecular mechanism of the herb have not been demonstrated clearly. MATERIALS AND METHODS: In our study, serum alanine aminotransferase, aspartate aminotransferase, and total bilirubin levels were examined after S. mussotii Franch. treatment of the acute liver injury on the carbon tetrachloride-induced rat model. Then, proteome analysis was conducted to explore the potential mechanism of SMT for hepatoprotective effects after iTRAQLC-MS/MS analysis (isobaric tag for relative and absolute quantification-liquid chromatography-mass spectrometer with tandem mass spectrometry). RESULTS: Serum results showed that alanine aminotransferase, aspartate aminotransferase, and total bilirubin levels of rats with acute liver injury were all improved with SMT treatment. Moreover, proteome analysis suggested that, with S. mussotii Franch. treatment, the levels of lipid catabolic process and lipid homeostasis were all enhanced. Furthermore, the results of protein-protein interaction (PPI) analysis illustrated that the proteins assembled in PPI networks were found to be significantly enriched in response to lipid, negative regulation of lipase activity, and in response to lipopolysaccharides. Furthermore, the down-regulated MRP14 and MRP8 proteins were found to be involved in the lipid metabolism, which may indicate the mechanism of SMT for the protection of the liver from ALI induced by carbon tetrachloride. CONCLUSION: SMT herb could play a role in hepatoprotection and alleviating the acute liver injury by impacting the lipid metabolism associated with the biological process.

Oxidative and Endoplasmic Reticulum Stress Responses to Chronic High-Altitude Exposure During the Development of High-Altitude Pulmonary Hypertension.

Pu, Xiaoyan, Xue Lin, Xianglan Duan, Junjie Wang, Jun Shang, Haixia Yun, and Zhi Chen. Oxidative and endoplasmic reticulum stress responses to chronic high-altitude exposure during the development of high-altitude pulmonary hypertension. High Alt Med Biol. 21:378-387, 2020. Objectives: To investigate the effect of endoplasmic reticulum (ER) stress during the development of high-altitude pulmonary hypertension (HAPH) after chronic high-altitude exposure, as well as the association between oxidative stress and ER stress. Methods: Forty male Sprague-Dawley rats were placed in a low-pressure chamber with a simulated altitude of 4,200 m for 0-28 days. Rats were chosen at random on days 0, 7, 14, and 28 of chronic high-altitude exposure and were examined for pulmonary arterial pressure, oxidative stress, apoptosis, and ER stress. Results: Chronic high-altitude exposure caused a continuous deterioration of pulmonary hypertension, which was accompanied by obvious apoptosis of alveolar epithelial cells and remodeling of pulmonary vessels. From day 7 of high-altitude exposure, although the activities of glutathione peroxidase and superoxide dismutase were gradually decreased, the generation of both malondialdehyde and reactive oxygen species was increased in a time-dependent manner. The protein expression of ER stress-related GRP78, PERK, IRE1α, ATF6, ATF4, CHOP, and caspase-12 in lung tissue was significantly upregulated from day 14 of high-altitude exposure. Further, the expression of caspase-12 in alveolar epithelial cells and vascular smooth muscle cells was also increased from day 14 of high-altitude exposure. Conclusions: Early high-altitude exposure first activates oxidative stress; then, it gradually activates ER stress. The activation of ER stress might promote the apoptosis of alveolar epithelial cells and the remodeling of pulmonary vessels by exacerbating the oxidative stress response during the development of HAPH after chronic high-altitude exposure.

Exploration of the Hepatoprotective Effect and Mechanism of Swertia mussotii Franch in an Acute Liver Injury Rat Model.

BACKGROUND AND OBJECTIVE: Swertia mussotii Franch, also known as "Zangyinchen", is one of a Tibetan traditional herb used for treatment of liver diseases over thousands of years at Qinghai-Tibet Plateau, has been confirmed to be hepatoprotective. However, the underlying mechanism is largely unknown. MATERIALS AND METHODS: In this study, we evaluated the effect of S. mussotii treatment in a carbon tetrachloride-induced acute liver injury rat model by examining the serum alanine aminotransferase, aspartate aminotransferase, total bilirubin levels and performing histological observations of the liver tissues. Meanwhile, the metabolomics analysis was used to explore the molecular mechanism of S. mussotii treatment by high performance liquid chromatography tandem mass spectrometry. RESULTS: The results showed that S. mussotii treatment could effectively improve the serum alanine aminotransferase, aspartate aminotransferase, total bilirubin in acute liver injury rat model. Histological observation showed that S. mussotii treatment could effectively alleviate liver injury. Moreover, the metabolomics analysis showed that S. mussotii treatment could normalize the levels of many fatty acid metabolism related metabolites. And the results of pathway analysis showed that these metabolites significantly enriched in fatty acid biosynthesis pathway (myristic acid, dodecanoic acid and capric acid) and linoleic acid metabolism pathway (13-OxoODE). CONCLUSION: The results indicated that S. mussotii treatment could significantly improve acute liver injury through affecting the pathways related to lipid metabolism.

Effect of aqueous extract of sanweitanxiang powder on calcium homeostasis protein expression in ischemic-reperfusion injury rat heart.

OBJECTIVE: To investigate the underlying mechanism of reduced myocardial ischemia-reperfusion (I/R) injury in rats using the traditional Tibetan medicine Sanweitanxiang powder (SWTX). METHODS: Rats were randomly divided into six groups (n = 10) as follows: (a) propranolol dinitrate control group, given propranolol dinitrate 0.02 g/kg for 10 days before I/R, (b) SWTX with a high dose group, given SWTX 1.5 g/kg for 10 days before I/R, (c) SWTX with a medium dose group, given SWTX 1.25 g/kg for 10 days before I/R, (d) sham group (Sham), in which the rat heart was exposed by pericardiotomy but without I/R, (e) SWTX with a low dose group, given SWTX 1.0 g/kg for 10 days before I/R, and (f) I/R injury group. Rats were intragastrically pretreated with propranolol dinitrate or SWTX. After that, the operation to cause ischemia and reperfusion was conducted. The histopathologic changes of rat hearts were observed by hematoxylin and eosin staining and transmission electron microscopy. Ca2+ homeostasis protein expression was determined by western blot. RESULTS: After SWTX pretreatment, the development of ultrastructural pathological changes from IR injury was attenuated. A decrease in the expression of B-cell lymphoma 2 associated X protein, and an increase in the expression of B-cell lymphoma 2 were observed. An increased activation of extracellular signal regulated kinases were found. Compared with the sham group, the expression of sarcoplasmic reticulum calcium-ATPase, phospholamban, and calsequestrin were all up-regulated after pretreatment with SWTX. CONCLUSION: The protective mechanism of SWTX pretreatment on myocardial I/R injury might be related to its effect on maintaining the balance of calcium homeostasis in rat heart.

Genetic evidence for high-altitude adaptation in Tibet.

Tibetans have lived at very high altitudes for thousands of years, and they have a distinctive suite of physiological traits that enable them to tolerate environmental hypoxia. These phenotypes are clearly the result of adaptation to this environment, but their genetic basis remains unknown. We report genome-wide scans that reveal positive selection in several regions that contain genes whose products are likely involved in high-altitude adaptation. Positively selected haplotypes of EGLN1 and PPARA were significantly associated with the decreased hemoglobin phenotype that is unique to this highland population. Identification of these genes provides support for previously hypothesized mechanisms of high-altitude adaptation and illuminates the complexity of hypoxia-response pathways in humans.

[Cloning and homologous analysis of coding region of alpha-globin gene from Tibetan antelope].

AIM: To clone and analyze the encoding region of alpha-globin gene from Tibetan antelope. METHODS: Total RNA was isolated from an adolescent Tibetan antelope liver, and Tibetan antelope alpha-globin gene was amplified by RT-PCR. The PCR product was cloned into pGEM-T vector and sequenced. Nucleotide sequences were compared with GenBank data by Blast method. RESULTS: The encoding region of alpha-globin gene of Tibetan antelope was obtained and deposited in GenBank as accession number DQ650713. Compared with sheep alpha-chain, alterations in important regions could be noted: a132 Asn-->Ser, a134 Ser-->Gly; but 19 differences were detected when compared with that of human. Phylogenetic analysis showed that the encoding region of alpha-globin gene of Tibetan antelope was most likely close to that of sheep and goat. CONCLUSION: The encoding region of gene Tibetan antelope alpha-globin gene is successfully cloned, which provides basic information for elucidating the possible role of hemoglobin in high altitude adaptation of Tibetan antelope.

[Electrophysiological study on rat conduit pulmonary artery smooth muscle cells under normoxia and acute hypoxia].

The present study was designed to investigate the electrophysiological characteristics of rat conduit pulmonary artery smooth muscle cells (PASMCs) and the response to acute hypoxia. PASMCs of the 1st to 2nd order branches in the conduit pulmonary arteries were obtained by enzymatic isolation. The PASMCs were divided into acute hypoxia preconditioned group and normoxia group. Hypoxia solutions were achieved by bubbling with 5% CO2 plus 95% N2 for at least 30 min before cell perfusion. Potassium currents were compared between these two groups using whole-cell patch clamp technique. The total outward current of PASMCs was measured under normoxia condition when iBTX [specific blocking agent of large conductance Ca-activated K(+) (BK(Ca)) channel] and 4-AP [specific blocking agent of delayed rectifier K(+) (K(DR)) channel] were added consequently into bath solution. PASMCs were classified into three types according to their size, shape and electrophysiological characteristics. Type I cells are the smallest with spindle shape, smooth surface and discrete perinuclear bulge. Type II cells show the biggest size with banana-like appearance. Type III cells have the similar size with type I, and present intermediary shape between type I and type II. iBTX had little effect on the total outward current in type I cells, while 4-AP almost completely blocked it. Most of the total outward current in type II cells was inhibited by iBTX, and the remaining was sensitive to 4-AP. In type III cells, the total outward current was sensitive to both iBTX and 4-AP. Acute hypoxia reduced the current in all three types of cells: (1614.8+/-62.5) pA to (892.4+/-33.6) pA for type I cells (P<0.01); (438.3+/-42.8) pA to (277.5+/-44.7) pA for type II cells (P<0.01); (1 042.0+/-37.2) pA to (613.6+/-23.8) pA for type III (P<0.01), and raised the resting membrane potentials (E(m)) in all these three types of cells: (-41.6+/-1.6) mV to (-18.6+/-1.5) mV (P<0.01), (-42.3+/-3.8) mV to (-30.6+/-3.0) mV (P<0.01), (-43.3+/-1.6) mV to (-28.4+/-1.4) mV (P<0.01), for type I, II, III cells, respectively. These results suggest that acute hypoxia suppresses the potassium current and improves the E(m) in PASMCs. These effects may be involved in the modulation of constriction/relaxation of conduit artery under acute hypoxia. Different distribution of K(DR) and BK(Ca) channels in these three types of PASMCs might account for their different constriction/relaxation response to acute hypoxia.