Recent studies have shown that the chemokine receptor CXCR3 and its ligand CXCL10 in the dorsal root ganglion mediate itch in experimental allergic contact dermatitis (ACD). CXCR3 in the spinal cord also contributes to the maintenance of neuropathic pain. However, whether spinal CXCR3 is involved in acute or chronic itch remains unclear. Here, we report that Cxcr3 mice showed normal scratching in acute itch models but reduced scratching in chronic itch models of dry skin and ACD. In contrast, both formalin-induced acute pain and complete Freund's adjuvant-induced chronic inflammatory pain were reduced in Cxcr3 mice. In addition, the expression of CXCR3 and CXCL10 was increased in the spinal cord in the dry skin model induced by acetone and diethyl ether followed by water (AEW). Intrathecal injection of a CXCR3 antagonist alleviated AEW-induced itch. Furthermore, touch-elicited itch (alloknesis) after compound 48/80 or AEW treatment was suppressed in Cxcr3 mice. Finally, AEW-induced astrocyte activation was inhibited in Cxcr3 mice. Taken together, these data suggest that spinal CXCR3 mediates chronic itch and alloknesis, and targeting CXCR3 may provide effective treatment for chronic pruritus.
Acetamides ; therapeutic use ; Animals ; Chemokine CXCL10 ; metabolism ; Chloroquine ; toxicity ; Chronic Disease ; Cyclopropanes ; adverse effects ; Dehydration ; complications ; Dinitrofluorobenzene ; adverse effects ; Disease Models, Animal ; Formaldehyde ; toxicity ; Freund's Adjuvant ; toxicity ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Motor Activity ; drug effects ; Pain ; chemically induced ; Pruritus ; chemically induced ; pathology ; Pyrimidines ; therapeutic use ; Receptors, CXCR3 ; antagonists & inhibitors ; genetics ; metabolism ; Skin ; pathology ; Spinal Cord ; drug effects ; metabolism ; pathology ; Time Factors ; p-Methoxy-N-methylphenethylamine ; toxicity

The aim of this study was to explore the mechanism of the nervous system lesions induced by formaldehyde (FA). Male Balb/c mice were exposed to gaseous formaldehyde for 7 days (8 h/d) with three different concentrations (0, 0.5 and 3.0 mg/m(3)). A group of animals injected with the nitric oxide synthase inhibitor L-NMMA (0.01 mL/g) was also set and exposed to 3.0 mg/m(3) FA. The concentrations of cAMP, cGMP, NO and the activity of NOS in cerebral cortex, hippocampus and brain stem were determined by corresponding assay kits. The results showed that, compared with the control (0 mg/m(3) FA) group, the cAMP contents in cerebral cortex and brain stem were significantly increased in 0.5 mg/m(3) FA group (P < 0.05), but decreased in 3.0 mg/m(3) FA group (P < 0.05); The concentration of cAMP in hippocampus was significantly decreased in 3.0 mg/m(3) FA group (P < 0.05). In comparison with the control group, L-NMMA group showed unchanged cAMP contents and NOS activities in different brain regions, but showed increased cGMP contents in hippocampus and NO contents in cerebral cortex (P < 0.05). In addition, compared with 3.0 mg/m(3) FA group, L-NMMA group showed increased contents of cAMP and reduced NOS activities in different brain regions, as well as significantly decreased cGMP contents in cerebral cortex and brain stem and NO content in brain stem. These results suggest that the toxicity of FA on mouse nervous system is related to NO/cGMP and cAMP signaling pathways.
Animals ; Brain Stem ; chemistry ; drug effects ; Cerebral Cortex ; chemistry ; drug effects ; Cyclic AMP ; chemistry ; Cyclic GMP ; chemistry ; Formaldehyde ; toxicity ; Hippocampus ; chemistry ; drug effects ; Male ; Mice ; Mice, Inbred BALB C ; Nitric Oxide ; chemistry ; Nitric Oxide Synthase ; antagonists & inhibitors ; omega-N-Methylarginine ; pharmacology

OBJECTIVETo study the role of poly (ADP-ribose) polymerase-l (PARP-1) in formaldehyde-induced DNA damage response in human bronchial epithelial (HBE) cells and to investigate the mechanism of formaldehyde carcinogenicity.

METHODSThe protein levels were measured by Western blot. The interaction between different proteins was determined by co-immunoprecipitation assay. The chemical inhibitor was used to confirm the relationship between PARP-1 and DNA damage repair.

RESULTSAfter being exposed to different concentrations of formaldehyde for 4 h, HBE cells showed no significant changes in cell viability. Cell viability was significantly reduced after 24-h exposure to 80 and 160 µmol/L formaldehyde (P < 0.05). The 10 µmol/L formaldehyde resulted in significant increases in the protein levels of PARP-1 and XRCC-1. However, 80 µmol/L formaldehyde led to a significant decrease in the protein level of PARP-1 of 124 KD molecular weight but a significant increase in the protein level of PARP-1 of 89 KD molecular weight; there was no significant change in the protein level of XRCC-1. The co-immunoprecipitation assay showed that 10 µmol/L formaldehyde induced increased binding between PARP-1 and XRCC-1, but 80 µmol/L formaldehyde led to no significant change in binding between PARP-1 and XRCC-1. Here, we confirmed the role of 10 µmol/L formaldehyde in strand breaks by comet assay which showed an increase in the tail DNA content of HBE cells after 4-h formaldehyde exposure. No significant difference was observed in tail DNA content between treated HBE cells and control cells at 2 h after formaldehyde was removed. Moreover, compared with control, inhibition of PARP-1 induced a significant increase in tail DNA content, and a significant difference was observed in tail DNA content between inhibited HBE cells and control cells at 2 h after formaldehyde was removed. Inhibition of PARP-1 significantly reduced DNA repair capacity.

CONCLUSIONPARP-1 mediated the repair of DNA damage induced by low-concentration formaldehyde through recruiting XRCC-1 protein, and may be involved in the regulation of cell apoptosis induced by high-concentration formaldehyde.

Apoptosis ; drug effects ; Cells, Cultured ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; DNA-Binding Proteins ; metabolism ; Epithelial Cells ; drug effects ; metabolism ; pathology ; Formaldehyde ; toxicity ; Humans ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerases ; metabolism ; X-ray Repair Cross Complementing Protein 1

OBJECTIVETo study the effects of intragastric administration of formaldehyde on lipid peroxidation in mice.

METHODSThirty ICR mice were randomly divided into 3 groups: one control group and two experimental groups. The mice were given formaldehyde (the dose is 0, 5 and 20 mg/kg body weight respectively) through intragastric administration once a day for 5 days , and then they were killed. The activities of SOD and the contents of MDA in liver were measured.

RESULTSThe activities of SOD in the 20 mg/kg body weight group were significantly lower than the control group (P < 0.05), and the contents of MDA in the 20 mg/kg body weight group were significantly higher than the control group (P < 0.05), and the liver organ coefficient in the 20 mg/kg body weight group is higher than the control group (P < 0.05).

CONCLUSIONA certain dose of formaldehyde can destroy the balance of lipid peroxidation in mice, the ability of antioxidation is reduced obviously, and the liver become compensatory hypertrophy.

Animals ; Female ; Formaldehyde ; toxicity ; Gastric Lavage ; Lipid Peroxidation ; Liver ; drug effects ; metabolism ; pathology ; Male ; Malondialdehyde ; metabolism ; Mice ; Mice, Inbred ICR ; Superoxide Dismutase ; metabolism

PURPOSE: Nociceptin/orphanin FQ (N/OFQ) as an endogeneous hexadecapeptide is known to exert antinociceptive effects spinally. The aims of this study were to demonstrate the antinociceptive effects of i.t. N/OFQ and to investigate the possible interaction between N/OFQ and endogenous opioid systems using selective opioid receptor antagonists in rat formalin tests. MATERIALS AND METHODS: I.t. N/OFQ was injected in different doses (1-10 nmol) via a lumbar catheter prior to a 50 microL injection of 5% formalin into the right hindpaw of rats. Flinching responses were measured from 0-10 min (phase I, an initial acute state) and 11-60 min (phase II, a prolonged tonic state). To observe which opioid receptors are involved in the anti-nociceptive effect of i.t. N/OFQ in the rat-formalin tests, naltrindole (5-20 nmol), beta-funaltrexamine (1-10 nmol), and norbinaltorphimine (10 nmol), selective delta-, micro- and kappa-opioid receptor antagonists, respectively, were administered intrathecally 5 min after i.t. N/OFQ. RESULTS: I.t. N/OFQ attenuated the formalin-induced flinching responses in a dose-dependent manner in both phases I and II. I.t. administration of naltrindole and beta-funaltrexamine dose-dependently reversed the N/OFQ-induced attenuation of flinching responses in both phases; however, norbinaltorphimine did not. CONCLUSION: I.t. N/OFQ exerted an antinociceptive effect in both phases of the rat-formalin test through the nociceptin opioid peptide receptor. In addition, the results suggested that delta- and micro-opioid receptors, but not kappa-opioid receptors, are involved in the antinociceptive effects of N/OFQ in the spinal cord of rats.
Analgesics/administration & dosage/*pharmacology ; Animals ; Formaldehyde/toxicity ; Injections, Spinal ; Male ; Naltrexone/administration & dosage/analogs & derivatives/pharmacology ; Narcotic Antagonists/administration & dosage/*pharmacology ; Opioid Peptides/administration & dosage/*pharmacology ; Pain Measurement ; Rats ; Rats, Sprague-Dawley ; Receptors, Opioid/*agonists/drug effects

OBJECTIVETo evaluate the anti-inflammatory and analgesic activities of leaf extract of Melanthera scandens (M. scandens).

METHODSThe crude leaf extract (39-111 mg/kg) of M. scandens was investigated for anti-inflammatory and analgesic activities using various experimental models. The anti-inflammatory activity was investigated using carragenin, egg-albumin induced oedema models, while acetic acid, formalin-induced paw licking and thermal-induced pain models were used to evaluate the antinociceptive property.

RESULTSThe extract caused a significant (P<0.05 - 0.001) dose-dependent reduction of inflammation and pains induced by different agents used.

CONCLUSIONSThe leaf extract possesses anti-inflammatory and analgesic effects which may be mediated through the phytochemical constituents of the plant.

Acetic Acid ; toxicity ; Albumins ; adverse effects ; Analgesics ; therapeutic use ; Animals ; Anti-Inflammatory Agents ; therapeutic use ; Asteraceae ; metabolism ; Carrageenan ; toxicity ; Edema ; drug therapy ; Formaldehyde ; toxicity ; Inflammation ; chemically induced ; drug therapy ; Mice ; Pain ; chemically induced ; drug therapy ; Phytochemicals ; therapeutic use ; Phytotherapy ; Plant Extracts ; therapeutic use ; Plant Leaves ; metabolism

OBJECTIVETo investigate the protective role of inducible heat shock protein 70 (Hsp70) against damage induced by formaldehyde.

METHODSHuman bronchial epithelium (HBE) cells were transfected with plasmid harboring hsp70 gene to increase the protein expression level. HBE cells transfected with pcDNA3.1 plasmid were used as transfection control and HBE cells cultured at normal condition served as control. Three groups were marked as HBE/hsp70, HBE/pcDNA and HBE. Hsp70 expression levels of 3 groups were detected. The cells of HBE/hsp70 and HBE groups were exposed to different concentrations of formaldehyde (0,0.39,1.56,6.25 mmol/L) for 4 h. The contents of GSH and MDA were measured, and KCl-SDS method was applied to measure DNA-protein crosslink (DPC).

RESULTSHsp70 level in HBE/hsp70 group increased by 80% compared with HBE group. GSH contents in HBE/hsp70 group significantly increased and were 141.0, 119.6 mg/gpro at 0.39, 1.56 mmol/L, respectively (P<0.01), as compared with HBE group. However, it decreased when formaldehyde concentration increased to 6.25 mmol/L. While GSH content in HBE group remained decreasing. MDA contents in HBE/hsp70 and HBE group increased with formaldehyde. MDA content in HBE/hsp70 was 0.088 micromol/gpro and significantly lower than that (0.138 micromol/gpro) in HBE group (P<0.05) when formaldehyde concentration was 1.56 mmol/L, At the formaldehyde dose of 6.25 mmol/L MDA content in HBE/hsp70 was 0.140 micromol/gpro which was significantly lower than that (0.289 micromol/gpro) in HBE group (P<0.01). DPC% in two groups increased with formaldehyde. At the formaldehyde dose of 0.39 mmol/L, DPC% in HBE/hsp70 group was 3.94% which was significantly lower than that (6.25%) in HBE group (P< 0.01). At the formaldehyde dose of 1.56 mmol/L, DPC% in HBE/hsp70 group was 11.86% which was significantly lower than that (20.89%) in HBE group (P<0.05).

CONCLUSIONHsp70 can reduce formaldehyde-induced damages in human bronchial epithelium cells in vitro.

Cells, Cultured ; Epithelial Cells ; drug effects ; metabolism ; Formaldehyde ; toxicity ; Glutathione ; metabolism ; HSP70 Heat-Shock Proteins ; metabolism ; Humans ; Malondialdehyde ; metabolism ; Transfection

OBJECTIVETo investigate the susceptibility to carbon tetrachloride and benzene in offspring of expanded simple tandem repeats (ESTR) mutation mice exposed to formaldehyde (FA).

METHODSF5 and F10 offspring (200 mg/m3 x 2 hours) served as H group and ICR mice were used as control group (group C). The F5 and F10 offspring were exposed to 10 ml/kg carbon tetrachloride at the doses of 0.05%, 0.50% or 5.00% for 24 hours, respectively or 500 or 1000 mg/kg benzene for 24 hours, respectively by intraperitoneal injection. Serum alanine transaminase (ALT), aspartate transaminase (AST) and the hepatic superoxide dismutase (SOD) or malondialdehyde (MDA) were detected; also the hepatic pathological changes were observed under light microscope; the micronucleus in sternum bone marrow cells as the biomarker of benzene blood toxicity were measured.

RESULTSALT and AST activities in group C of F5 mice exposed to 0.50% and 5.00% CCl4, ALT in groups C and H of F10 mice exposed to 0.05%, 0.50%, 5.00% CCl4, AST in groups C and H of F10 mice exposed to 0.50% and 5.00% CCl4 were significantly higher than those in controls, respectively (P<0.05); as compared to the control, hepatic SOD activities in group C of F5 and F10 mice exposed to 0.50% and 5.00% CCl4, in group H of F5 mice exposed to 0.50% and 5.00% CCl4 and F10 mice exposed to 5.00% CCl4 were significantly reduced, respectively (P<0.05); however, MDA contents in group C of F10 mice exposed to 0.50% and 5.00% CCl4, in group H of F5 mice exposed to 0.05% and 0.50%, 5.00% CCl4 and F10 mice exposed to 0.50% and 5.00% CCl4 were significantly increased than those in control group, respectively (P<0.05). The susceptibility to CCl4 in ESTR mutation F5 mice exposed to FA was significantly higher than that in control F5 mice, but the susceptibility to CCl4 in ESTR mutation F10 mice exposed to FA was significantly lower than that in control F10 mice. The histopathological examination showed that the injury of hepatocytes in C and H groups significantly increased CCl4 doses, and the injury of hepatocytes in H group was higher than that in C group. The micronuclear rates in C and H group mice exposed to benzene(500 mg/kg C group, F5 and F10 mice; 1000 mg/kg C group, F5 and F10 mice; 500 mg/kg H group, F5 and F10 mice; 1000 mg/kg C group, F5 and F10 mice) were 5.88 per thousand +/- 4.55 per thousand, 8.25 per thousand +/- 2.06 per thousand, 7.50 per thousand +/- 6.99 per thousand, 10.67 per thousand +/- 1.16 per thousand, 7.88 per thousand +/- 3.09 per thousand, 9.20 per thousand +/- 1.30 per thousand, 9.63 per thousand +/- 4.34 per thousand and 13.33 per thousand +/- 2.08 per thousand, respectively, which were significantly higher than those (1.13 per thousand +/- 0.35 per thousand, 1.20 per thousand +/- 0.82 per thousand, 1.25 per thousand +/- 0.46 per thousand, 1.33 per thousand +/- 1.03 per thousand) in the solvent control group (P<0.05 or P<0.01).

CONCLUSIONFA could result in the change of susceptibility to CCl4 and benzene in offspring of ESTR mutation mice. ESTR mutation may be a biomarker of the susceptibility to chemicals, but the molecular mechanisms should be investigated in the future.

Alanine Transaminase ; metabolism ; Animals ; Aspartate Aminotransferases ; metabolism ; Benzene ; toxicity ; Carbon Tetrachloride ; toxicity ; Chemical and Drug Induced Liver Injury ; Environmental Exposure ; Female ; Formaldehyde ; toxicity ; Genetic Predisposition to Disease ; Liver ; drug effects ; pathology ; Male ; Malondialdehyde ; metabolism ; Mice ; Mice, Inbred ICR ; Mutation ; Superoxide Dismutase ; metabolism ; Tandem Repeat Sequences ; genetics

OBJECTIVETo investigate the effects of formaldehyde inhalation on the morphological damage, and Glu, GABA and NOS contents in olfactory bulb and hippocampus of rats.

METHODSTwenty SD rats were equally divided into two groups: rats in the control group inhaled fresh air, while the animals in experimental group were exposed to the air containing formaldehyde (12.5 mg/m(3), 4 h/d) for 7 days. Then rats were sacrificed and frozen sections of olfactory bulb and hippocampus were prepared. The morphological changes were examined and the Glu, GABA and NOS contents were detected using Nissl-staining, immunohistochemistry and Western blot, respectively.

RESULTCompared with the control group, there was a significant confusion and shrink of neuron morphology in experimental group, the number and staining intensity of Glu and NOS positive cells and protein contents were reduced. The protein expression of GABA was also decreased in the formaldehyde group.

CONCLUSIONFormaldehyde inhalation can cause a severe morphological damage of olfactory bulb and hippocampus in SD rats,which may further impair memory and learning ability through the reduction of Glu, GABA and NOS expression.

Animals ; Formaldehyde ; toxicity ; Glutamic Acid ; metabolism ; Hippocampus ; drug effects ; metabolism ; pathology ; Inhalation Exposure ; Learning ; drug effects ; Neurons ; drug effects ; metabolism ; pathology ; Nitric Oxide Synthase ; metabolism ; Olfactory Bulb ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; metabolism

Animals ; Brain ; cytology ; Cerebrospinal Fluid ; physiology ; Formaldehyde ; administration & dosage ; toxicity ; Inflammation ; chemically induced ; physiopathology ; Male ; Neurons ; metabolism ; physiology ; Pain ; chemically induced ; physiopathology ; Pain Measurement ; methods ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; metabolism