Objective: To investigate the effects of nicotine on the morphology, structure of offspring's dental germ, enamel organ and other dental tissues and the further potential epigenetic mechanisms by establishing prenatal nicotine exposure mouse model. Methods: Ten C57BL/6 pregnant mice were randomly divided into control group (physiological saline subcutaneous injection) and prenatal nicotine exposure (PNE) group (nicotine subcutaneous injection) by using a random number table. Postnatal day 0 (P0), postnatal day 14 (P14) and postnatal day 25 (P25) offspring mice were collected for subsequent experiments. The offspring mice were divided into offspring control group and offspring PNE group according to the maternal group respectively. Weights of P0 and P25 offspring mice were recorded. Micro-CT, scanning electron microscope (SEM) and Vickers hardness test were performed to analyze the related parameters of hard tissues including alveolar bones and mandibular incisors. Total RNAs were extracted from mandible tissues and the third generation of dental epithelial stem cells (DESC) in P25 mice. The relative expression levels of osteogenic and ameloblastic differentiation related genes were measured by real-time quantitative PCR (RT-qPCR). Immunohistochemical stainings of paraffin sections were then performed to observe the distribution and expression level of proliferating cell nuclear antigen (Pcna), amelogenin (Amelx), histone H3 trimethylated at lysine 27 (H3K27me3) and enhancer of zeste homolog 2 (Ezh2). Cell counting kit-8 (CCK-8) assays were used to detect the cell viabilities of DESCs after administrations of different concentrations of nicotine (0.01, 0.1, 1 mmol/L) and GSK126 (an inhibitor of histone methyltransferase Ezh2). Results: Compared with the control group, pregnant mice in PNE group were more likely to have adverse pregnancy outcomes, such as significantly lower offspring body weight [P0: offspring control (1.20±0.04) g, offspring PNE (0.99±0.02) g, P<0.001; P25: offspring control (15.26±1.70) g, offspring PNE (9.65±1.32) g, P<0.001] and increased stillbirths rate [offspring control (0), offspring PNE (46.40±9.30) %, P<0.001]. At P14 and P25, the distance parameters between the enamel mineralized deposits of mandibular incisors and the mesial surface of the first molar in offspring PNE group [P14: (-1 349±45) μm; P25: (-1 192±147) μm] was significantly decreased compared with the control group [P14: (-506±380) μm, P25: (504±198) μm] (P<0.05, P<0.001). The enamel column and enamel column stroma of incisors in offspring PNE group were blurred, arranged loosely and disorderly than those in the control group, while the microhardness of incisor enamel in offspring PNE group [(245.7±18.4) MPa] was significantly lower compared to the control group [(371.9±28.7) MPa] (P<0.001). HE staining showed disordered pre-ameloblast (Pre-Am) arrangement and delayed mineralization deposition point in offspring PNE group compared with the control group, while the length of transit-amplifying cell (TA) and Pre-Am region were prolonged as well. Immunohistochemical staining results displayed that the overall Pcna (P<0.05), H3K27me3 (P<0.01), Ezh2 (P<0.01) expression of labial cervical loop (LaCL) in PNE group were increased, while the positive signal of Amelx in ameloblast cytoplasm was impaired. In vitro, the addition of 1 mmol/L nicotine could significantly upregulate the expression level of Pcna (P<0.01) and downregulate the expression levels of B lymphoma Mo-MLV insertion region 1 (P<0.05), leucine rich repeats and immunoglobulin like domains 1 (P<0.05), Amelx (P<0.01). In addition, 1 mmol/L nicotine could also significantly enhance the proliferation activity of DESCs (P<0.001). Addition of 10 μmol/L GSK126, could rescue the proliferation activation effect of 1 mmol/L nicotine on DESCs. Conclusions: PNE may delay the process of enamel formation and lineage differentiation, leading to the abnormal proliferation of DESCs and changes of epigenetic modification state in H3K27me3, which affect the development of enamel in offspring mice,suggesting PNE might be one of risk environmental factor for tooth development.
Pregnancy ; Female ; Mice ; Animals ; Nicotine/toxicity* ; Proliferating Cell Nuclear Antigen ; Histones ; Mice, Inbred C57BL ; Dental Enamel

OBJECTIVE: To compare the effects of electroacupuncture (EA) at "Zusanli" (ST 36) versus "Yanglingquan" (GB 34) in the pregnant rats on perinatal nicotineexposureinduced lung function and morphology of newborn rats and explore the rule of acupoint effect in EA for the prevention from lung dysplasia in newborn rats. METHODS: A total of 24 female SD rats were randomized into a normal saline group (S group), a nicotine group (N group), a nicotineST 36 group (N + ST 36 group) and a nicotineGB 34 group (N+GB 34 group), 6 rats in each one. Starting at the 6th day of pregnancy, 0.9% sodium chloride solution was injected subcutaneously in the S group, 1 mg/kg; and in the rest 3 groups, nicotine of the same dose was injected through to the 21st postnatal day to establish the perinatal nicotineexposure model. Simultaneously, during model preparation, EA was applied at "Zusanli" (ST 36) and "Yanglingquan" (GB 34) in the N+ST 36 group and the N+GB 34 group respectively, once a day, through to the 21st postnatal day. The lung function analytic system for small animal was adopted to observe the changes in lung function indicators in newborn rats, such as peak inspiratory flow (PIF), peak expiratory flow (PEF), expiratory resistance (RE), inspiratory resistance (RI) and dynamic compliance (Cdyn). HE staining was used to observe the morphological changes of lung, such as alveolar fusion and rupture. RESULTS: Compared with the S group, PEF and Cdyn were lower and PIF, RI and RE higher in the N group (all <0.01), additionally, alveoli were fused and ruptured, alveolar wall thickened, the numbers of alveoli reduced, the interspace of alveoli enlarged and the diameter increased (<0.01). Compared with the N group, in the N+ST 36 group, PEF and Cdyn were increased, PIF, RI and RE reduced (<0.05, <0.01), the alveolar fusion and rupture relieved, the numbers of alveoli increased, alveolar wall thinner, the interpsace of alveoli became normal and the diameter was reduced significantly (<0.01). In the N+GB 34 group, the changes of lung function and morphological indicators were not significant (>0.05). CONCLUSION Electroacupuncture at "Zusanli" (ST 36) in the pregnant rats significantly improves the perinatal nicotineexposureinduced lung function and morphology of newborn rats than electroacupuncture at "Yanglingquan" (GB 34).
Acupuncture Points ; Animals ; Animals, Newborn ; Electroacupuncture ; Female ; Lung ; drug effects ; physiopathology ; Nicotine ; toxicity ; Pregnancy ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the effects of nicotine on endogenous carbon monoxide (CO) concentration and nitric oxide synthase (NOS) activity in the corpus cavernosum of adult male rats, and explore the possible mechanism of cigarette smoking affecting erectile dysfunction.

METHODSForty adult male rats were equally divided into three treatment groups to receive subcutaneous injection of nicotine at 0.5 mg/kg pre d for 1, 2 and 3 months, and a control group to receive saline only. After treatment, the corpus cavernosum was harvested for detection of CO concentration by modified two-wavelength spectrophotometry and NOS activity by improved Griess measurement.

RESULTSCO concentration and NOS activity were decreased by 9.05 and 13.37%, respectively, after 1 month of nicotine injection (P < 0.01), 16.47 and 22.5% after 2 months (P < 0.01), and 22.99 and 31.74% after 3 months (P < 0.01), as compared with (13.664 +/- 0.404) umol/mg prot and (9.721 +/- 0.470) U/mg prot in the control group.

CONCLUSIONNicotine can reduce endogenous CO concentration and NOS activity in the corpus cavernosum of adult male rats, which suggests the involvement of endogenous CO and NOS in the pathophysiological process of smoking-induced erectile dysfunction .

Animals ; Carbon Monoxide ; metabolism ; Erectile Dysfunction ; chemically induced ; Male ; Nicotine ; toxicity ; Nitric Oxide Synthase ; metabolism ; Penis ; metabolism ; Rats ; Smoking ; adverse effects

OBJECTIVETo evaluate the potency of carboxymethyl chitosan-2, 2' ethylenedioxy bis-ethylamine-folate (CMC-EDBE-FA) on tissue injury, antioxidant status and glutathione system in tissue mitochondria and serum against nicotine-induced oxidative stress in mice.

METHODSCMC-EDBE-FA was prepared on basis of carboxymethyl chitosan tagged with folic acid by covalently linkage through 2, 2' ethylenedioxy bis-ethylamine. Animals were divided into four groups, i.e., control, nicotine (1 mg/kg bw/day), CMC-EDBE-FA (1 mg/kg bw/day) and nicotine (1 mg/kg bw/day) and CMC-EDBE-FA (1 mg/kg bw/day) for 7 days. Levels of lipid peroxidation, oxidized glutathione level, antioxidant enzyme status and DNA damage were observed and compared.

RESULTSThe significantly increase of lipid peroxidation, oxidized glutathione levels and DNA damage was observed in nicotine treated group as compared with control group; those were significantly reduced in CMC-EDBE-FA supplemented group. Moreover, significantly reduced antioxidant status in nicotine treated group was effectively ameliorated by the supplementation of CMC-EDBE-FA. Only CMC-EDBE-FA treated groups showed no significant change as compared with control group; rather than it repairs the tissue damage of nicotine treated group.

CONCLUSIONSThese findings suggest that CMC-EDBE-FA is non-toxic and ameliorates nicotine-induced toxicity.

Animals ; Antioxidants ; chemistry ; pharmacology ; Chitosan ; analogs & derivatives ; chemistry ; pharmacology ; DNA Fragmentation ; drug effects ; Folic Acid ; chemistry ; pharmacology ; Glutathione ; analysis ; metabolism ; Glutathione Transferase ; metabolism ; Male ; Mice ; Nanoparticles ; chemistry ; Nicotine ; toxicity ; Organ Specificity ; Oxidoreductases ; metabolism

OBJECTIVETo investigate the cellular effects of cigarette smoke extract (CSE) on primarily cultured human umbilical vein endothelial cells (HUVEC).

METHODSThe effects of CSE (5%-20%) and nicotine (10(-4) mol/L) on HUVEC viability, proliferation, angiogenesis and apoptosis were observed.

RESULTSCSE decreased HUVEC survival rate and angiogenesis after 24 h as well as its proliferation after 48 h in a dose-dependent manner. Moreover, CSE induced apoptosis of HUVEC as indicated in condensation of nuclear chromatin and the presence of hypodiploid DNA. HUVEC incubated with CSE for 24 h gave a significant decrease in the expression of Bcl-2 as well as the decline in the Bcl-2/Bax ratio accompanied with the loss of mitochondrial membrane potential and excess cytosolic calcium. Our study also observed that p53 protein level decreased, rather than increased in cells treated with CSE. Nicotine had no discernible inhibitory effects on the above indices of HUVEC.

CONCLUSIONExposure to CSE other than nicotine causes inhibition of viability, proliferation and differentiation of HUVEC. CSE-induced HUVEC injury is mediated in partthrough accelerated apoptosis but independent of p53 pathway. It appears that mitochondria have played a key role in the apoptosis of HUVEC induced by CSE.

Angiogenesis Inhibitors ; pharmacology ; Apoptosis ; Calcium ; analysis ; Cell Cycle ; drug effects ; Cell Differentiation ; drug effects ; Cell Survival ; drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Endothelial Cells ; drug effects ; metabolism ; pathology ; Endothelium, Vascular ; drug effects ; pathology ; Humans ; Membrane Potentials ; Mitochondria ; drug effects ; metabolism ; Nicotine ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; Smoke ; Tobacco ; toxicity ; Tumor Suppressor Protein p53 ; biosynthesis ; Umbilical Veins ; bcl-2-Associated X Protein

OBJECTIVETo investigate the toxicity of cigarette smoke extract (CSE) and nicotine on mouse brain mitochondria as well as the protective effect of vitamin C in vitro.

METHODMouse brain mitochondria in vitro was incubated with CSE or nicotine in the absence or presence of vitamin C for 60 minutes, and the changes of mitochondrial function and structure were measured.

RESULTSCSE inhibited mitochondrial ATPase and cytochrome C oxidase activities in a dose-dependent manner. However, no significant changes in the peroxidation indices were observed when mitochondrial respiratory enzymes activity was inhibited, and protection of mitochondria from CSE-induced injury by vitamin C was not displayed in vitro. The effect of CSE on mouse brain mitochondria swelling response to calcium stimulation was dependent on calcium concentrations. CSE inhibited swelling of mitochondria at 6.5 mumol/L Ca2+, but promoted swelling response at 250 mumol/L Ca2+. Nicotine, the major component of cigarette smoke, showed no significant damage in mouse brain mitochondria in vitro. The CSE treatment induced mitochondrial inner membrane damage and vacuolization of the matrix, whereas the outer mitochondrial membrane appeared to be preserved.

CONCLUSIONThe toxic effect of CSE on brain mitochondria may be due to its direct action on enzymatic activity rather than through oxygen free radical injury. Nicotine is not the responsible component for the toxicity of CSE to brain mitochondria.

Adenosine Triphosphatases ; pharmacology ; Animals ; Antioxidants ; pharmacology ; Ascorbic Acid ; pharmacology ; Brain ; pathology ; Electron Transport Complex IV ; pharmacology ; Free Radicals ; Ganglionic Stimulants ; toxicity ; Mice ; Mitochondria ; pathology ; Nicotine ; toxicity ; Smoke ; adverse effects ; Tobacco

OBJECTIVETo evaluate the effects of nicotine and tobacco extract (ST) on PDLFs morphology, structure, proliferation and attachment.

METHODSPDLFs were cultured in the presence of nicotine and ST at various concentration. The cell changes in the morphology and structure were examined by histological and transmission electrical microscope (TEM). The growth and attachment of cell were measured by MTT method.

RESULTSThe size of the cells became smaller gradually and their shapes changed from shuttle type to oval or round when the concentration of nicotine and ST increased, the polarity of the cells was in disorder, ultrastructure showed that the organelles, especially rough-surfaced endoplasmic reticulum and golgi complex decreased in number, microtubule and microfilaments were disassembled, the nuclei became fewer or shrunk, the growth and attachment were dose-dependently inhibited.

CONCLUSIONSNicotine and ST can change PDLFs' morphology and structure, they may inhibit the growth and attachment through disruption of the cytoskeleton, suggesting nicotine and ST may have pathological role on human periodontitis.

Cell Adhesion ; drug effects ; Cell Division ; drug effects ; Fibroblasts ; cytology ; Humans ; Nicotine ; toxicity ; Periodontal Ligament ; drug effects ; pathology ; ultrastructure ; Plant Extracts ; toxicity ; Tobacco

OBJECTIVETo provide a useful biological index for clinical diagnosis of Alzheimer's disease (AD) by determination the functional changes in the central cholinergic nerve and their effects on the peripheral lymphatic system.

METHODSThe learning and memory impairment model was established through intraventricular injecting quinolinic acid (QA) repeatedly.

RESULTSThere was a significant decline of cholineacetyltransferase (ChAT) in cerebral cortex and hippocampus after QA injection. The significantly lower binding activities of acetylcholine muscarinic (M) and nicotinic (N) cholinergic receptors in the hippocampus and cortex in the QA group were found as compared with the sham-operated group (P < 0.01). Similar changes were found in the binding activities of M-and N-receptors on spleen lymphocytes.

CONCLUSIONCertain lesion of the central nervous system can be reflected in peripheral spleen lymphocytes, which may be an important reference to diagnose the changes of the central nervous system.

Alzheimer Disease ; etiology ; Animals ; Brain ; drug effects ; Choline O-Acetyltransferase ; metabolism ; Disease Models, Animal ; Learning ; drug effects ; Male ; Memory ; drug effects ; Nicotine ; metabolism ; Quinolinic Acid ; toxicity ; Quinuclidinyl Benzilate ; metabolism ; Rats ; Rats, Wistar ; Receptors, Cholinergic ; analysis ; drug effects