Mycoplasma infection is the most prevalent contamination in cell culture. Analysis of cell culture in laboratories from different countries shows that mycoplasma contamination ranges from 15% to 80% and, in some cases, even reaches 100% (Chernov et al., 2014). Whilst mycoplasma infection is not visible to the naked eye in cell culture, the consequences of mycoplasma contamination have been shown to induce a number of cellular changes, for example, increased resistance to chemotherapeutic drugs. Therefore, any results obtained from tissue culture studies, in the presence of mycoplasma contamination, potentially render the data invalid (Kim et al., 2015; Gedye et al., 2016). As such, mycoplasmas are not harmless bystanders and cannot be ignored in in vitro studies.
Arginine/pharmacology* ; HEK293 Cells ; Humans ; Mycoplasma/isolation & purification* ; Plasmids ; Transfection

The present study investigated the effect of emodin on the serum metabolite profiles in the chronic constriction injury(CCI) model by non-target metabolomics and explored its analgesic mechanism. Twenty-four Sprague Dawley(SD) rats were randomly divided into a sham group(S), a CCI group(C), and an emodin group(E). The rats in the emodin group were taken emodin via gavage once a day for fifteen days(50 mg·kg~(-1)) on the first day after the CCI surgery. Mechanical withdrawal threshold(MWT) and thermal withdrawal threshold(TWL) in each group were performed before the CCI surgery and 3,7, 11, and 15 days after surgery. After 15 days, blood samples were collected from the abdominal aorta. The differential metabolites were screened out by non-target metabolomics and analyzed with Kyoto Encyclopedia of Genes and Genomes(KEGG) and ingenuity pathway analysis(IPA). From the third day after CCI surgery, the MWT and TWL values were reduced significantly in both CCI group and emodin group, compared with the sham group(P<0.01). At 15 days post-surgery, the MWT and TWL values in emodin group increased significantly compared with the CCI group(P<0.05). As revealed by non-target metabolomics, 72 differential serum metabolites were screened out from the C-S comparison, including 41 up-regulated and 31 down-regulated ones, while 26 differential serum metabolites from E-C comparison, including 10 up-regulated and 16 down-regulated ones. KEGG analysis showed that the differential metabolites in E-C comparison were enriched in the signaling pathways, such as sphingolipid metabolism, arginine biosynthesis, glycerophospholipid metabolism, and tryptophan metabolism. IPA showed that the differential metabolites were mainly involved in the lipid metabolism-molecular transport-small molecule biochemistry network. In conclusion, emodin can exert an analgesic role via regulating sphingolipid metabolism and arginine biosynthesis.
Analgesics/pharmacology* ; Animals ; Arginine ; Emodin/pharmacology* ; Neuralgia/metabolism* ; Rats ; Rats, Sprague-Dawley ; Sphingolipids

Microcystin-leucine arginine (MC-LR), a potentially carcinogenic toxin, is produced by Cyanobacteria such as Microcystis and Ananabacteria during water bloom. Increasing evidence demonstrated that MC-LR induces male reproductive toxicity, mainly by inducing germ cell apoptosis, destroying cell cytoskeleton, interfering with DNA damage repair pathway, and damaging blood-testicular barrier (BTB), which eventually lead to male sterility. Testicular Sertoli cells are the somatic cells that directly contact with spermatogenic cells in seminiferous tubules. They not only regulate immune response to maintain testicular immune homeostasis by secreting a variety of cytokines and immunosuppressive factors, but also provide the protective effects of spermatogenic cells by forming BTB. MC-LR induces inflammation and apoptosis of Sertoli cells, and destroys the integrity of the BTB, and then causes spermatogenesis dysfunction.
Male ; Humans ; Sertoli Cells ; Leucine/pharmacology* ; Arginine/pharmacology* ; Microcystins/metabolism* ; Immunity

AIMTo observe the effect of nonselective nitro oxide synthase inhibitor N(G)-nitro-L-arginine(L-NA) on mitochondria injury in focal cerebral ischemia rats.

METHODSThe rats were randomly divided into sham, ischemia and L-NA treatment group. The model of focal cerebral ischemia was prepared with thread embolism in rats. L-NA was administrated respectively at 2 h, 6 h, 12 h after middle cerebral artery occlusion (MCAO). Rats were killed and the mitochondria of cerebral tissue were isolated by differential centrifugation after L-NA treatment for 3 days. The swelling and the activity of mitochondria, and the activities of ATPase, SOD, GSH-Px in mitochondria and the contents of NO, MDA in mitochondria were measured. Ultrastructure changes of neuronal mitochondria were examined by electronic microscope in ischemia and L-NA treatment group.

RESULTSThe swelling of mitochondria was markedly increased and the activity of mitochondria was decreased, and the contents of mitochondria NO and MDA were markedly increased, the activity of ATPase, SOD and GSH-Px in mitochondria were decreased significantly after MCAO. Compared with ischemia group, the contents of NO were decreased after ischemia 2h, 6h, 12h administered by L-NA, and the swelling of mitochondria was decreased and the activity of mitochondria was increased, and the activities of ATPase, SOD, GSH-Px in mitochondria were enhanced and the contents of MDA in mitochondria were decreased after ischemia 12 h administered by L-NA. The neuronal cytoplasm and the mitochondria swelled, the cristae were disrupted, dissolved or disappeared in MCAO rats. Administration of L-NA could reduce these changes induced by cerebral ischemia in rats.

CONCLUSIONIt could be concluded that L-NA could beneficially inhibit NO production. But it could't protect brain against damage in ischemia acute stage. It could improve mitochondria energy pump, ameliorate oxidative injury and increase the activities of mitochondria during postischemia, and then could effectively protect brain against damage induced by focal cerebral ischemia.

Animals ; Arginine ; pharmacology ; Brain ; metabolism ; Brain Ischemia ; metabolism ; pathology ; Male ; Mitochondria ; metabolism ; pathology ; Rats ; Rats, Wistar

This article analyzed the mechanism of Danggui Sini Decoction(DSD) in improving kidney injury caused by blood stasis syndrome(BSS) in rats. Firstly, 32 female SD rats were randomly divided into the following four groups: a normal group and a BSS group, both receiving an equal amount of distilled water by gavage; a normal+DSD group and a BSS+DSD group, both receiving 5.103 g·kg~(-1) DSD orally for a total of 14 days. Daily cold water bath was given to establish the BSS model, and on the 14th day, BSS rats were subcutaneously injected with 0.8 mg·kg~(-1) adrenaline. Normal rats were subjected to the water bath at 37 ℃ and injected with an equal volume of distilled water. After the experiment, 24-hour urine, serum, and kidney samples were collected for metabolomic analysis, biochemical measurements, and hematoxylin-eosin(HE) staining. The study then employed ~1H-NMR metabolomic technology to reveal the metabolic network regulated by DSD in improving BSS-induced kidney injury and used network pharmacology to preliminarily elucidate the key targets of the effectiveness of DSD. Pathological and biochemical analysis showed that DSD intervention significantly reduced inflammation and abnormal levels of blood creatinine, blood urea nitrogen, and urine protein in the kidneys. Metabolomic analysis indicated that DSD attenuated BSS-induced kidney injury primarily by regulating 10 differential metabolites and three major metabolic pathways(taurine and hypotaurine metabolism, citrate cycle, and acetaldehyde and dicarboxylic acid metabolism). Network pharmacology analysis suggested that the protective effect of DSD against BSS-induced kidney injury might be related to two key genes, ATP citrate lyase(ACLY) and nitric oxide synthase 2(NOS2), and two main metabolic pathways, i.e., arginine biosynthesis, and arginine and proline metabolism. This study, from the perspective of network regulation, provides initial insights and evidence into the mechanism of DSD in improving kidney injury induced by BSS, offering a basis for further investigation into the molecular mechanisms underlying its efficacy.
Rats ; Female ; Animals ; Rats, Sprague-Dawley ; Network Pharmacology ; Drugs, Chinese Herbal/chemistry* ; Metabolomics ; Kidney ; Arginine ; Water

AIMTo further explore the roles of endogenous nitric oxide (NO) or NO derivatives in complex partial seizures and generalized convulsions.

METHODSThe effect of pretreatment with L-nitroarginine (L-NNA), an inhibitor of nitric oxide synthase (NOS), or L arginine (L-Arg), a precursor of NO on kainic acid (KA)-induced seizure in rats and the changes in the concentration of NO2 -/NO- in the hippocampus were determined.

RESULTSThe rats appeared with wet dog shakes (WDS) at 15 min and then occurred generalized convulsions during 1 h to 3 h after administration of KA (10 mg/kg i.p.). However, the pretreatment of L-NNA (50 mg/kg) so dramatically promoted and enhanced KA-induced behavioral seizures that the latency of generalized convulsion was shorten dramatically, and the mortality was greatly high. In contrast, the pretreatment with L-Arg (40 mg/kg) markedly delayed or weakened KA-induced behavioral changes, such as increasing latency of WDS and generalized convulsion, shortening time o f seizure and none of animal died during observed time. The concentration of NO2- /NO3- in the hippocampus increased immediately at 30 min and remained to 7 d after the administration of KA. Compared with control group (pretreatment with NS), the concentration of NO2- / NO3- in the hippocampus apparently increased at 3 h and 3 d after the administration of KA in the rats with L-Arg pretreatment.

CONCLUSIONThe endogenous NO (NO or NO derivatives) mediators may play an important role against excitotoxin induced seizures in rats.

Animals ; Arginine ; pharmacology ; Kainic Acid ; adverse effects ; Male ; Nitric Oxide ; metabolism ; Nitroarginine ; pharmacology ; Rats ; Rats, Wistar ; Seizures ; chemically induced ; metabolism

AIMIn order to discover new inhibitors and enhancers of nitric oxide synthase (NOS), an in vitro assay to determine NOS activity was established for high throughput screening.

METHODSThe activity of NOS was detected based on the change of nicotinamide-adenine dinucleotide phosphate (NADPH) concentration in the reaction system by the fluorescence density. The enzyme was prepared from bovine brain by gradient centrifugation. The reaction performed in black 96 well micro-plate with a final volume of 90 microL. Every factor which would affect the results such as the concentration of NADPH, L-arginine (L-Arg, used as substrate) and enzyme protein was optimized in different conditions. At last, 5,600 samples (compounds and extracts) were screened by the method.

RESULTSThe test signal (fluorescence density) in the reaction system was influenced by many different factors such as temperature and concentration of substrates. The ideal system contains protein 1.50 mg.mL-1, L-Arg 1 mmol.L-1, NADPH 0.1 mmol.L-1 at 37 degrees C. In this method, there were about 2% samples which emit fluorescence, and about 0.5% samples which quench the fluorescence. So these samples were deleted from the sample library. The effects of these samples on activity of NOS were distributed in a normal manner. About 2% samples had potential effects on the NOS activity (including inhibitors and enhancers).

CONCLUSIONThe method can be performed by high throughput screening and gives the stable data, not only for inhibitors, but also for enhancers of NOS activity.

Animals ; Arginine ; pharmacology ; Cattle ; Drug Evaluation, Preclinical ; methods ; Enzyme Inhibitors ; isolation & purification ; pharmacology ; In Vitro Techniques ; NADP ; pharmacology ; Nitric Oxide Synthase ; antagonists & inhibitors ; metabolism ; Nitroarginine ; pharmacology

OBJECTIVETo evaluate the effects of arginine modified chitosan or hexadecylated modified chitosan as gene carriers on the cellular uptake by vascular smooth muscle cells and its in vitro cytotoxicity. METHODS Plasmid DNA was labeled with alpha-32P-dATP and complexed with the modified chitosans or unmodified chitosan to form nanoparticle complexes by complex coacervation method. Uptake of all kinds of chitosan/ DNA nanoparticle complexes (CNC) by A10 cells was measured by beta-liquid scintillation counting. The in vitro cytotoxicity of the CNC was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay.

RESULTSThe diameters of the CNC ranged from 55.9-174.9 nm and the zeta potentials were from 10. 8 mV for the arginine modified chitosan/DNA nanoparticle complexes (ACNC) to 1.8 mV for the hexadecylated chitosan/DNA nanoparticle complexes (HCNC). The cellular uptake of the modified chitosan/ DNA nanoparticle complexes (MCNC) by A10 cells increased significantly when compared with the unmodified chitosan/DNA nanoparticle complexes (UCNC) (P < 0.05), with the HCNC at N/P ratio of 1:1 and the ACNC at ratio of 8:1 showing the highest cellular uptake (1.3 fold higher than UCNC, P < 0.05). MCNC were much less cytotoxic when compared with Lipofectamine 2000-DNA nanoparticles.

CONCLUSIONDNA nanoparticle complexes prepared with either arginine or hexadecylated modified chitosan can improve the cellular uptake of the DNA, while the in vitro cytotoxicity of both of the modified chitosan is much less than that of Lipofectamine 2000.

Animals ; Antigen-Antibody Complex ; Arginine ; pharmacology ; Chitosan ; chemistry ; pharmacology ; Citric Acid ; analogs & derivatives ; pharmacology ; Cytotoxicity, Immunologic ; DNA ; pharmacology ; Genetic Vectors ; Nanoparticles ; Rats

OBJECTIVETo investigate the effects of a novel tripeptide analog of arginine on isoproterenol (ISO), a beta-adrenergic receptor agonist, induced the change in concentration transient cytosolic free calcium in cultured neonatal rat cardiac myocytes (CMs).

METHODSThe expression of inducible nitric oxide synthase (iNOS) was induced in cultured neonatal rat CMs by stimulation with lipopolysaccharide (LPS) and interleukin-6 (IL-6) for 24 h, and quantitatively measured using Western blotting. The CMs were incubated in the presence of the new arginine analog for 6 h and the changes of fluorescence signal of free calcium in response to isoproterenol (ISO) treatment were measured under laser scanning confocal microscope.

RESULTSIncubation of the CMs for 24 h in the presence of IL-6 and LPS resulted in significantly increased nitric oxide (NO) production, and also in increased iNOS protein accumulation in the cells. Specific inhibition of iNOS by the new arginine analog substantially inhibited NO production and increased the peak value of ISO-induced Ca2+ transient.

CONCLUSIONThe new arginine analog strongly inhibits IL-6 and LPS-induced NO production and increases beta-adrenergic responsiveness in cultured neonatal rat CMs.

Animals ; Animals, Newborn ; Arginine ; analogs & derivatives ; pharmacology ; Calcium ; metabolism ; Cells, Cultured ; Isoproterenol ; pharmacology ; Myocytes, Cardiac ; cytology ; drug effects ; metabolism ; Oligopeptides ; pharmacology ; Rats ; Rats, Sprague-Dawley

Adenosine ; pharmacology ; Anesthetics, Inhalation ; pharmacology ; Arginine ; pharmacology ; Cardiac Surgical Procedures ; methods ; Heart Arrest, Induced ; Humans ; Ischemic Preconditioning, Myocardial ; Myocardial Reperfusion Injury ; prevention & control ; Nitric Oxide ; physiology