Endophytic Bacillus pumilus G5 Interacting with Silicon to Improve Drought Stress Resilience in Glycyrrhiza uralensis Fisch. by Modulating Nitrogen Absorption, Assimilation, and Metabolism Pathways.

Drought stress has become the primary severe threat to global agriculture production, including medicinal plants. Plant growth-promoting bacteria (PGPB) and environmentally friendly element silicon (Si) have emerged as effective methods in alleviating drought stress in various plants. Here, the effects of the plant endophytic G5 interaction with Si on regulating nitrogen absorption, assimilation, and metabolism pathways were investigated in the morphophysiological and gene attributes of Glycyrrhiza uralensis exposed to drought. Results showed that G5+Si application improved nitrogen absorption and assimilation by increasing the available nitrogen content in the soil, further improving the nitrogen utilization efficiency. Then, G5+Si triggered the accumulation of the major adjustment substances proline, γ-aminobutyric acid, putrescine, and chlorophyll, which played an important role in contributing to maintaining balance and energy supply in G. uralensis exposed to drought. These findings will provide new ideas for the combined application of PGPR and Si on both soil and plant systems in a drought habitat.

Key points for protecting the external branch of the superior laryngeal nerve in open thyroidectomy: A possible exploration technique.

OBJECTIVE: Injury of the external branch of the superior laryngeal nerve (EBSLN) is easily overlooked in thyroidectomy, and voice changes caused by the injury have a negative effect on an increasing number of patients. This study aimed to reduce the injury rate of EBSLN by expanding the sternothyroid-laryngeal triangle and standardizing the exploration procedure. METHODS: A total of 520 patients who had undergone thyroidectomy at the First Affiliated Hospital of Nanchang University between September 2021 and April 2022 were analyzed. During the operation, the exposure rate of the EBSLN before and after sternothyroid-laryngeal triangle expansion was compared, and all EBSLNs were anatomically classified. RESULTS: The exposure rate of EBSLN after sternothyroid-laryngeal triangle expansion reached 82.7%, which is much higher than that before sternothyroid-laryngeal triangle expansion (33.7%), and voice change caused by injury of the EBSLN was reported in one case (the injury rate was 0.2%). The classification and proportion of the EBSLN were as follows: Type 1 (55.3%), the nerve ran within 1 cm above the STP, but no coincidence or crossover with blood vessels was observed in this region; Type 2 (14.7%), the nerve travelled within 1 cm above the STP and overlapped or intersected with blood vessels in this region; Type 3 (12.7%), the EBSLN ran below the level of the STP; and Type 4 (17.3%), no EBSLN was observed within 1 cm above the STP. CONCLUSION: In thyroidectomy, injury to the EBSLN can be effectively reduced by expanding the sternothyroid-laryngeal triangle and exploring the upper pole area of the thyroid as far as possible, which has great clinical significance in reducing postoperative voice box injury.

UVRAG cooperates with cargo receptors to assemble the ER-phagy site.

ER-phagy is a selective autophagy process that targets specific regions of the endoplasmic reticulum (ER) for removal via lysosomal degradation. During cellular stress induced by starvation, cargo receptors concentrate at distinct ER-phagy sites (ERPHS) to recruit core autophagy proteins and initiate ER-phagy. However, the molecular mechanism responsible for ERPHS formation remains unclear. In our study, we discovered that the autophagy regulator UV radiation Resistance-Associated Gene (UVRAG) plays a crucial role in orchestrating the assembly of ERPHS. Upon starvation, UVRAG localizes to ERPHS and interacts with specific ER-phagy cargo receptors, such as FAM134B, ATL3, and RTN3L. UVRAG regulates the oligomerization of cargo receptors and facilitates the recruitment of Atg8 family proteins. Consequently, UVRAG promotes efficient ERPHS assembly and turnover of both ER sheets and tubules. Importantly, UVRAG-mediated ER-phagy contributes to the clearance of pathogenic proinsulin aggregates. Remarkably, the involvement of UVRAG in ER-phagy initiation is independent of its canonical function as a subunit of class III phosphatidylinositol 3-kinase complex II.

Bacillus cereus G2 Facilitates N Cycle in Soil, Further Improves N Uptake and Assimilation, and Accelerates Proline and Glycine Betaine Metabolisms of Glycyrrhiza uralensis Subjected to Salt Stress.

Soil salinity is a severe abiotic stress that reduces crop productivity. Recently, there has been growing interest in the application of microbes, mainly plant-growth-promoting bacteria (PGPB), as inoculants for saline land restoration and plant salinity tolerance. Herein, the effects of the plant endophyte G2 on regulating soil N cycle, plant N uptake and assimilate pathways, proline and glycine betaine biosynthesis, and catabolic pathways were investigated in Glycyrrhiza uralensis exposed to salinity. The results indicated that G2 improved the efficiency of N absorption and assimilation of plants by facilitating soil N cycling. Then, G2 promoted the synthesis substrates of proline and glycine betaine and accelerated its synthesis rate, which increased the relative water content and reduced the electrolyte leakage, eventually protecting the membrane system caused by salt stress in G. uralensis. These findings will provide a new idea from soil to plant systems in a salinity environment.

Dietary Effects on Monocyte Phenotypes in Subjects With Hypertriglyceridemia and Metabolic Syndrome.

In patients with hypertriglyceridemia, a short-term low-saturated fat vs high-saturated fat diet induced lower plasma lipids and improved monocyte phenotypes. These findings highlight the role of diet fat content and composition for monocyte phenotypes and possibly cardiovascular disease risk in these patients. (Effects of Dietary Interventions on Monocytes in Metabolic Syndrome; NCT03591588).

Physio-biochemical and transcriptomic analysis reveals that the mechanism of Bacillus cereus G2 alleviated oxidative stress of salt-stressed Glycyrrhiza uralensis Fisch. seedlings.

Salt stress severely affects the growth and productivity of Glycyrrhiza uralensis. Our previous research found that the endophyte Bacillus cereus G2 alleviated the osmotic and oxidative stress in G. uralensis exposed to salinity. However, the mechanism is still unclear. Here, a pot experiment was conducted to analyse the change in parameters related to osmotic adjustment and antioxidant metabolism by G2 in salt-stressed G. uralensis at the physio-biochemistry and transcriptome levels. The results showed that G2 significantly increased proline content by 48 %, glycine betaine content by 75 % due to activated expression of BADH1, and soluble sugar content by 77 % due to upregulated expression of α-glucosidase and SS, which might help to decrease the cell osmotic potential, enable the cell to absorb water, and stabilize the cell's protein and membrane structure, thereby alleviating osmotic stress. Regarding antioxidant metabolism, G2 significantly decreased malondialdehyde (MDA) content by 27 %, which might be ascribed to the increase in superoxide dismutase (SOD) activity that facilitated the decrease in the superoxide radical (O2‾) production rate; it also increased the activities of catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX), which helped stabilize the normal level of hydrogen peroxide (H2O2). G2 also increased glutathione (GSH) content by 65 % due to increased glutathione reductase (GR) activity and GSH/GSSG ratio, but G2 decreased oxidized glutathione (GSSG) content by 13 % due to decreased activity of dehydroascorbate reductase (DHAR), which could provide sufficient substrates for the ascorbate-glutathione (AsA-GSH) cycle to eliminate excess H2O2 that was not cleared in a timely manner by the antioxidant enzyme system. Taken together, G2 alleviated osmotic stress by increasing proline, soluble sugar, and glycine betaine contents and alleviated oxidative stress by the synergistic effect of antioxidant enzymes and the AsA-GSH cycle. Therefore, the results may be useful for explaining the mechanism by which endophyte inoculation regulates the salt tolerance of crops.

Poloxamer 407 Induces Hypertriglyceridemia but Decreases Atherosclerosis in Ldlr-/- Mice.

BACKGROUND: Hypertriglyceridemia (HTG) increases the risk for atherosclerotic cardiovascular disease, but underlying mechanisms are incompletely understood. Circulating monocytes play an important role in atherogenesis by infiltrating arterial walls, where they differentiate into macrophages. We tested the hypothesis that HTG is mechanistically linked to atherogenesis by altering the monocyte phenotype and infiltration into atherosclerotic lesions in a model of diet-induced atherogenesis in Ldlr-/- mice. METHODS: HTG was induced in male Ldlr-/- mice, fed a Western, high-fat high-cholesterol diet, by daily injection of poloxamer 407 (P407), a lipoprotein lipase inhibitor, for seven weeks. Atherosclerosis, monocyte phenotypes, and monocyte migration into atherosclerotic lesions were determined by well-validated methods. RESULTS: Compared with the saline control, P407 injection in Ldlr-/- mice rapidly induced profound and persistent HTG, modestly elevated plasma cholesterol levels, and increased levels of triglyceride and cholesterol carried in very-low-density lipoprotein and low-density lipoprotein. Unexpectedly, mice receiving P407 versus saline control showed less atherosclerosis. Following induction of HTG by P407, CD36+ (also CD11c+), but not CD36- (CD11c-), monocytes showed early increases in lipid accumulation, but the number of CD36+ (not CD36-) monocytes was dramatically decreased afterwards in the circulation until the end of the test. Concurrently, CD36+ (CD11c+) monocyte migration into atherosclerotic lesions was also reduced in mice receiving P407 versus controls. CONCLUSIONS: P407 induced severe HTG, but reduced atherosclerosis, in Ldlr-/- mice, possibly because of profound reductions of circulating CD36+ (CD11c+) monocytes, leading to decreased monocyte migration into atherosclerotic lesions.

Inflammatory Links Between Hypertriglyceridemia and Atherogenesis.

PURPOSE OF REVIEW: Recent studies indicate an association between hypertriglyceridemia (HTG) and atherosclerotic cardiovascular disease (ASCVD). The purpose of this review is to discuss the potential mechanism connecting HTG and ASCVD risk and the potential efficacy of HTG-targeting therapies in ASCVD prevention. RECENT FINDINGS: HTG, with elevations in triglyceride-rich lipoproteins (TGRL) and their remnants, are causal ASCVD risk factors. The mechanisms whereby HTG increases ASCVD risk are not well understood but may include multiple factors. Inflammation plays a crucial role in atherosclerosis. TGRL compared to low-density lipoproteins (LDL) correlate better with inflammation. TGRL remnants can penetrate endothelium and interact with macrophages leading to foam cell formation and inflammation in arterial walls, thereby contributing to atherogenesis. In addition, circulating monocytes can take up TGRL and become lipid-laden foamy monocytes, which infiltrate the arterial wall and may also contribute to atherogenesis. Novel therapies targeting HTG or inflammation are in development and have potential of reducing residual ASCVD risk associated with HTG. Clinical and preclinical studies show a causal role of HTG in promoting ASCVD, in which inflammation plays a vital role. Novel therapies targeting HTG or inflammation have potential of reducing residual ASCVD risk.

Borneol-modified tanshinone IIA liposome improves cerebral ischemia reperfusion injury by suppressing NF-κB and ICAM-1 expression.

OBJECTIVE: To investigate the metabolism and brain tissue distribution of borneol-modified tanshinone IIA liposome (BO-TA-Lip) and its effect on NF-κB and ICAM-1 in cerebral ischemia reperfusion rats, thereby exploring the ameliorative mechanism of BO-TA-Lip on ischemic encephalopathy. METHODS: Particle size, entrapment efficiency, drug loading were measured to evaluate the preparation comprehensively. Metabolism and brain tissue distributions in vivo were measured by HPLC, and the pharmacokinetic parameters were calculated. In addition, 24 SD rats were randomly divided into sham, model, STS (sodium tanshinone IIA sulfonate, 30 mg/kg) and BO-TA-Lip groups (44 mg/kg). The middle cerebral artery occlusion (MCAO) rats were constructed with thread embolism method. Neurological deficits were scored using Zea Longa scoring standard. TTC and HE staining were used for the cerebral infarction and histopathological examination, respectively. The protein expression was examined by immunohistochemistry and Western blot. RESULTS: The average particle size, encapsulation efficiency and drug loading of BO-TA-Lip were (135.33 ± 7.25) nm, (85.95 ± 3.20)% and (4.06 ± 0.31)%, respectively. Both in the pharmacokinetic analysis of plasma and brain tissue, in BO-TA-Lip group, the peak concentration and the area under the curve increased, and the clearance rate decreased. The neurological deficit scores and infarct area of the BO-TA-Lip group were significantly lower than that of the model and STS groups. Besides, BO-TA-Lip reduced the protein expression of NF-κB, ICAM-1, IL-1ß, TNF-α and IL-6 in the brain tissue. CONCLUSION: BO-TA-Lip had higher bioavailability and better absorption in brain tissue, and could improve cerebral ischemia reperfusion injury, which might be related to the inhibitory effect of BO-TA-Lip in expression of NF-κB and ICAM-1.

Monocyte phenotyping and management of lipoprotein X syndrome.

BACKGROUND: Accumulation of lipoprotein X (LpX) in blood can cause severe hypercholesterolemia and cutaneous xanthomas. Monocytes sensitively sense lipid changes in circulation and contribute to inflammation. However, how monocytes respond to LpX is undefined. OBJECTIVE: We examined the phenotype of monocytes from a patient, who had LpX, severe hypercholesterolemia, and extensive cutaneous xanthomas, and effects of semiselective plasmapheresis therapy (SPPT). METHOD: Fluorescence-activated cell sorting and adhesion assays were used to examine monocyte phenotype and ex vivo oxidized low-density lipoprotein uptake and adhesion in the patient before and after treatment with SPPT. Effects of plasma from the patient on the phenotype and adhesion of monocytes from a healthy participant were determined. RESULTS: SPPT improved hypercholesterolemia and cutaneous xanthomas. Before treatment, the patient had lower frequency of nonclassical monocytes but higher frequency of intermediate monocytes than the control participant. Before treatment, monocytes from the patient with LpX showed more intracellular lipid accumulation, alterations in several cell surface markers and intracellular cytokines, as well as enhanced oxidized low-density lipoprotein uptake and reduced adhesion compared with control. After SPPT, the phenotypes of monocytes from the patient with LpX were similar to control monocytes. Incubation with plasma from the patient before treatment as compared with plasma from the control participant or the patient after treatment increased CD11c expression and adhesion of monocytes from a healthy participant. CONCLUSION: LpX-induced hypercholesterolemia increased lipid accumulation and altered the phenotype of monocytes, which may contribute to cutaneous xanthoma development. Removal of LpX by SPPT reduced lipid accumulation and improved monocyte phenotype, likely contributing to xanthoma resolution.

Replacing Saturated Fat With Unsaturated Fat in Western Diet Reduces Foamy Monocytes and Atherosclerosis in Male Ldlr-/- Mice.

OBJECTIVE: A Mediterranean diet supplemented with olive oil and nuts prevents cardiovascular disease in clinical studies, but the underlying mechanisms are incompletely understood. We investigated whether the preventive effect of the diet could be due to inhibition of atherosclerosis and foamy monocyte formation in Ldlr-/- mice fed with a diet in which milkfat in a Western diet (WD) was replaced with extra-virgin olive oil and nuts (EVOND). Approach and Results: Ldlr-/- mice were fed EVOND or a Western diet for 3 (or 6) months. Compared with the Western diet, EVOND decreased triglyceride and cholesterol levels but increased unsaturated fatty acid concentrations in plasma. EVOND also lowered intracellular lipid accumulation in circulating monocytes, indicating less formation of foamy monocytes, compared with the Western diet. In addition, compared with the Western diet, EVOND reduced monocyte expression of inflammatory cytokines, CD36, and CD11c, with decreased monocyte uptake of oxLDL (oxidized LDL [low-density lipoprotein]) ex vivo and reduced CD11c+ foamy monocyte firm arrest on vascular cell adhesion molecule-1 and E-selectin-coated slides in an ex vivo shear flow assay. Along with these changes, EVOND compared with the Western diet reduced the number of CD11c+ macrophages in atherosclerotic lesions and lowered atherosclerotic lesion area of the whole aorta and aortic sinus. CONCLUSIONS: A diet enriched in extra-virgin olive oil and nuts, compared with a Western diet high in saturated fat, lowered plasma cholesterol and triglyceride levels, inhibited foamy monocyte formation, inflammation, and adhesion, and reduced atherosclerosis in Ldlr-/- mice.

A novel AMPK activator improves hepatic lipid metabolism and leukocyte trafficking in experimental hepatic steatosis.

A novel AMP-activated protein kinase (AMPK) activator, IMM-H007 (H007), has been reported to reduce serum lipid levels and inhibit lipid accumulation in the liver in hyperlipidemic animal models. However, how H007 ameliorates hepatic steatosis and inflammation remains unknown. In the present study, H007, at 200 mg/kg, reduced hepatic lipid levels and the levels of collagenous fiber in the liver in high-fat diet (HFD)-fed hamsters compared to those in the HFD group. Meanwhile, compared to the controls, H007 significantly inhibited sterol-regulatory element binding protein (SREBP)-1c and acetyl CoA carboxylase (ACC) expression by upregulating the AMPK activity, suppressing the saturated fatty acid accumulation and increasing polyunsaturated fatty acid synthesis in the liver. Compared to the controls, H007 treatment inhibited the expression of monocyte chemotactic protein (MCP-1) in fatty acid-treated HepG2 cells; suppressed leukocyte adherence and rolling on the liver microvasculature; and suppressed hepatic macrophage infiltration. H007 also suppressed the expression of nuclear factor-κB (NF-κB) p65 in fatty acid- and lipopolysaccharide-treated HepG2 cells compared to that in the controls by activating AMPK. These data suggested that H007 had a beneficial effect by improving the lipid composition in the liver and inhibiting inflammatory cell trafficking in the development of nonalcoholic fatty liver disease.

Photocatalytic antibacterial agent incorporated double-network hydrogel for wound healing.

A novel antibacterial hydrogel was prepared through the addition of IT to a chitin (CT) and polyvinyl alcohol (PVA) hydrogel, creating a promising material for wound dressings. The addition of nano particles IT endowed the anti-bacterial activity of hydrogel as well as had a positive impact on the mechanical properties of the hydrogels. The structure of the prepared hydrogel dressing was characterized by FTIR, XPS, XRD, SEM and TEM. The composite hydrogel exhibited excellent anti-bacterial activity under the visible light. Cytotoxicity tests (L929 fibroblast cells) showed all samples achieving up to 80% cell viability. Furthermore, compared with conventional dressings, wound healing test revealed that CT/PVA/IT hydrogel could accelerated wound healing in vivo, wound closure rates reached 95.5% after 10 days. This study suggests that the novel hydrogel has considerable potential for applications in wound dressings.

The cordycepin derivative IMM-H007 improves endothelial dysfunction by suppressing vascular inflammation and promoting AMPK-dependent eNOS activation in high-fat diet-fed ApoE knockout mice.

2',3',5'-Tri-O-acetyl-N6-(3-hydroxyphenyl) adenosine, a cordycepin derivative that is also known as IMM-H007, is a new adenosine analogue and anti-hyperlipidaemic drug that was developed in our laboratory. It has been previously reported to alleviate atherosclerosis by regulating blood lipid levels. The purpose of the current study was to determine the protective effects of IMM-H007 on endothelial function and vascular inflammation independent of its lipid-lowering effect. Vascular reactivity was determined using a pressure myography system-120CP. Vascular inflammation was assessed to quantify leukocyte-endothelial adhesion in the mesenteric microcirculation. Relative levels of endothelial nitric oxide synthase（eNOS）activity were detected using a fluorescent nitric oxide（NO）probe, and NO production was detected using Griess reagent. Atherosclerotic plaques were evaluated with en face and cross section analyses. Here, IMM-H007 improved endothelial dysfunction through a mechanism independent of its lipid-lowering effect. IMM-H007 suppressed vascular inflammation both in the initial stage and during the progression of atherosclerosis. The in vitro study using human umbilical vein endothelial cells (HUVECs) revealed that IMM-H007 increased eNOS activity and nitric oxide production, which were closely related to the increased phosphorylation of AMP-activated protein kinase (AMPK), protein kinase B (Akt) and eNOS induced by IMM-H007. Furthermore, inhibition of AMPK by Compound C completely blocked IMM-H007-induced Akt and eNOS activation. IMM-H007 suppressed the formation of atherosclerotic lesions in ApoE-/- mice. We have presented evidence that IMM-H007 represents a potential therapeutic strategy to improve endothelial function and attenuate inflammation, and it is a promising, novel therapeutic approach to treating atherosclerosis.

Enhanced photocarriers separation of novel CdS/pt/Mo2C heterostructure for visible-light-driven hydrogen evolution.

The production of H2 from water using photocatalysts is a promising way of generating clean, renewable and alternative energy. The key issue is to develop active and stable photocatalysts. Here, we report a novel CdS/Pt/Mo2C heterostructure photocatalyst, where Pt nanoparticles are closely supported on CdS/Mo2C. The UV-vis spectrum and EIS Nyquist plots show that Mo2C can boost the absorption in the UV-vis region and improve the separation of the photogenerated electron-hole pairs from CdS. The Pt nanoparticles act as the active co-catalyst that promotes the transient photocurrent response. As a result, the CdS/Pt/Mo2C photocatalyst exhibits an excellent H2 evolution activity up to 1828.82 µmol h-1 g-1 under visible-light irradiation, 8.5 and 16.2 times higher than that of pristine CdS and CdS/Mo2C, respectively. Moreover, a high apparent quantum yield (AQY) of 9.39% is obtained at 400 nm for the CdS/Pt/Mo2C heterostructure photocatalyst.

Applications of Higenamine in pharmacology and medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Aconitum has been used as local and traditional medicines in many asian regions for the treatment of various diseases such as collapse, syncope, painful joints, oedema, bronchial asthma et al. Higenamine, a plant-based alkaloid, was initially isolated from Aconitum and identified as the active cardiotonic component of Aconitum. It has been tested as a candidate of pharmacologic stress agent in the detection of coronary artery diseases (CADs) and now researchers have just accomplished the phase III clinical studies successfully in China. Besides, a large number of studies have revealed the various pharmacological properties and potentially multi-spectral medical applications of higenamine. However, to date, no comprehensive review on higenamine has been published. AIM OF THE REVIEW: This present paper aims to compile a comprehensive update regarding the biochemistry, pharmacokinetic features, pharmacological activities, clinical and potential clinical uses and toxicities on higenamine with the ultimate objective of providing a guide for future research on this drug. MATERIALS AND METHODS: The selection of relevant data was made through a search using the keyword "higenamine" in "Web of science", "Pubmed", and "China Knowledge Resource Integrated (CNKI)". Information was also acquired from local classic herbal literature, government reports and conference papers. RESULTS: In addition to Aconitum, higenamine also exists in many other plants including Tinospora crispa, Nandina domestica THUNBERG, Gnetum Parvifolium C.Y. Cheng, sarum Heterotropoides,Nelumbo nucifera,N.nucifera. The pharmacokinetic studies conducted in animals and humans showed that higenamine conformed to a two-compartment pharmacokinetic model. Studies over the last four decades on higenamine have revealed its various pharmacological properties such as positive inotropic and chronotropic effect, activating slow channel effect, vascular and tracheal relaxation effect, anti-thrombotic, anti-apoptotic and anti-oxidative effect, anti-inflammatory and immunomodulatory effect. This phytochemical constituent has shown its potential therapeutic effects for diseases like heart failure, disseminated intravascular coagulation (DIC), shock, arthritis, asthma, ischemia/reperfusion (I/R) injuries and erectile dysfunction. CONCLUSIONS: Extensive basic and clinical studies on higenamine showed valuable therapeutic effects on different disorders. However, the underlying mechanisms of higenamine have not been established. Therefore, the safety, tolerability and efficacy of higenamine are as yet, not fully understood. Additionally, some of the studies were small sample-sized and unreliable. To sum up, there is a need for deeper investigation in the mechanisms of higenamine action, as well as well-designed preclinical and clinical trials studies to test the safety and clinical value of the drug.

Organic cation transporter 1 mediates the uptake of monocrotaline and plays an important role in its hepatotoxicity.

Monocrotaline (MCT) is a kind of toxic retronecine-type pyrrolizidine alkaloids (PAs) from plants of Crotalaria, which can be bio-activated by cytochrome P450 (CYP) enzymes in liver and then induce hepatotoxicity. Since CYPs are localized in the endoplasmic reticulum, the influx of MCT to the liver is the key step for its hepatotoxicity. The objective of the present study was to investigate the role of organic cation transporter 1 (OCT1), a transporter mainly expressed in liver, in the uptake of MCT and in hepatotoxicity induced by MCT. The results revealed that MCT markedly inhibited the uptake of 1-methyl-4-phenylpyridinium (MPP(+)), an OCT1 substrate, in Madin-Darby canine kidney (MDCK) cells stably expressing human OCT1 (MDCK-hOCT1) with the IC50 of 5.52±0.56µM. The uptake of MCT was significantly higher in MDCK-hOCT1 cells than in MDCK-mock cells, and MCT uptake in MDCK-hOCT1 cells followed Michaelis-Menten kinetics with the Km and Vmax values of 25.0±6.7µM and 266±64pmol/mg protein/min, respectively. Moreover, the OCT1 inhibitors, such as quinidine, d-tetrahydropalmatine (d-THP), obviously inhibited the uptake of MCT in MDCK-hOCT1 cells and isolated rat primary hepatocytes, and attenuated the viability reduction and LDH release of the primary cultured rat hepatocytes caused by MCT. In conclusion, OCT1 mediates the hepatic uptake of MCT and may play an important role in MCT induced-hepatotoxicity.