OBJECTIVETo confirm the expression and distribution of aquaporin 5 (AQP5) in rat nasal mucosa of experimental allergic rhinitis and to investigate the relationship between AQP5 and allergic rhinitis.

METHODSTwenty-four healthy Wistar rats both male and female weighting 200-300 g were divided into two groups randomly, one was testing group (n = 12), the other was comparing group (n = 12). Generally sensitized rats in testing group were given repeated local booster sensitization into nasal cavity. Twelve normal rat nasal mucosa and twelve nasal mucosa from rat with allergic rhinitis were used. The distribution of AQP5 in normal rat nasal mucosa and nasal mucosa in rat with allergic rhinitis were observed by immunofluorescence technique. Furthermore, the expression of AQP5 in normal rat nasal mucosa and nasal mucosa from rat with allergic rhinitis were studied by immunohistochemical staining.

RESULTSHematoxylin and eosin staining showed that there was obvious inflammation reaction, a large quantity of glands hyperplasia and acidophils soaked in nasal mucosa from rat with allergic rhinitis. (2) Both immunofluorescence technique and immunohistochemical staining showed that the distribution of AQP5 in normal rat nasal mucosa was in accordance with that in nasal mucosa from rat with allergic rhinitis on the whole. AQP5 expressed mainly in the membrane and cytoplasm of the epithelium in the glands, ducts and cilia. (3) The statistical analysis of the immunohistochemical staining showed that the quantity of AQP5 in rat nasal mucosa with allergic rhinitis (156.37 +/- 1.93) was obviously higher than that in the normal rat nasal mucosa (178.52 +/- 1.94). There was statistical significance between the two groups (t = 28.08, P < 0.01).

CONCLUSIONSThe hypersecretion of glands has a close relationship with the high expression of AQP5 in allergic rhinitis.

Animals ; Aquaporin 5 ; metabolism ; Female ; Male ; Nasal Mucosa ; metabolism ; Rats ; Rats, Wistar ; Rhinitis, Allergic, Perennial ; metabolism

Muscarinic acetylcholine receptors (mAChRs), including M1-M5 subtypes, are classic receptors in regulating water, ion, and solute transport in salivary gland. Our work focuses on the studies on the expression pattern and function of mAChR in the submandibular gland (SMG), and the underlying mechanism involved in the mAChR-regulated secretion, together with the effect of parasympathectomy on the salivary secretion. Microvascular autotransplantation of SMG into the temporal fossa provides a continuous and endogenous source of fluids, and is currently an effective method for treating severe keratoconjunctivitis sicca. By using RT-PCR, Western blotting, and immunofluorescence, our data demonstrated that the expression of M1 and M3 subtypes were decreased in latent period in rabbit SMG autotransplantation model, whereas carbachol stimulation promoted the salivary secretion, as well as M1 and M3 expressions. By contrast, mAChRs were hypersensitive in epiphora SMGs, whereas atropine gel and botulinum toxin A application significantly inhibited the hypersecretion in both animal models and patients. Furthermore, the possible intracellular signal molecules involved in the mAChR-modulated salivary secretion were explored. Activation of mAChR upregulated the expression of aquaporin 5 (AQP5), the main transporter that mediated water secretion through transcellular pathway, and led to AQP5 trafficking from lipid rafts to non-lipid microdomain. Extracellular signal-regulated kinase 1/2 (ERK1/2) was involved in the mAChR-regulated AQP5 content. mAChR activation also modulated the expression, distribution, and function of tight junction proteins, and increased paracellular permeability. ERK1/2/β-arrestin2/clathrin/ubiquitin signaling pathway was responsible for the mAChR-regulated downregulation of tight junction molecule claudin-4. Cytoskeleton filamentous actin (F-actin) was also involved in the distribution and barrier function of epithelial tight junctions. Besides, endothelial tight junctions were opened by mAChR agonist-evoked salivation in the mice. Furthermore, parasympathetic denervation increased resting salivary secretion in the long terminrats and minipigs. Taken together, our work demonstrated that mAChR regulated saliva secretion via transcellular and paracellular pathways in SMG epithelium as well as tight junction opening in SMG endothelium. Modulation of mAChR might be a promising strategy to ameliorate SMG dysfunction.
Animals ; Aquaporin 5 ; Carbachol ; Humans ; Mice ; Rabbits ; Receptors, Muscarinic ; Salivation ; Submandibular Gland

OBJECTIVE: To observe the effect of methyl eugenol on the expression of aquaporin (AQP) 5 in nasal mucosa of rats with allergic rhinitis and to explore its significance. METHODS: In the study, 128 Wistar rats were randomly divided into normal control group, AR model control group, budesonide positive control group, 80 mg/kg group, 40 mg/kg group, 20 mg/kg group and 10 mg/kg group, and ovalbumin (OVA) was used to establish the model of allergic rhinitis. After successful modeling, castor oil, budesonide and corresponding doses of methyl eugenol were given respectively. After 1, 2 and 4 weeks of administration, the distribution of AQP5 in nasal mucosa was observed by immunohistochemistry. The expression of AQP5 in nasal mucosa of each group was compared by Western blotting. The expression of AQP5 mRNA was compared with real-time PCR. RESULTS: AQP5 was mainly located in the glandular epithelium and ductal epithelial cell membrane and cytoplasm. The expression of AQP5 and AQP5 mRNA in nasal mucosa of the rats in the model control group was lower than that in the normal control group (P<0.05). AQP5 and AQP5 mRNA in nasal mucosa of the rats in each treatment group were higher than those in the model control group in varying degrees. The expression of AQP5 in the budesonide group was not significantly different from that in the normal control group 1, 2 and 4 weeks after drug intervention (P>0.05), but there was significant difference between the budesonide group and the model control group (P<0.05). The expression of AQP5 mRNA in the budesonide group was significantly different from that in the normal control group and the model control group (P<0.05).After 2 weeks of intervention, the expression of AQP5 in each dose group of methyleugenol was not significantly different from that in the budesonide group (P>0.05). After 1 week of intervention, there was no significant difference in AQP5 mRNA between the 20 mg/kg group and the normal control group (P>0.05), but there was significant difference between the 20 mg/kg group and the model control group (P<0.05). CONCLUSION Methyl eugenol may increase the degree of edema of the nasal mucosa by reducing the expression of AQP5 and reduce the secretion of glands, thus alleviating the symptoms of allergic rhinitis, sneezing and runny nose.
Animals ; Aquaporin 5 ; Eugenol/analogs & derivatives* ; Nasal Mucosa ; Rats ; Rats, Wistar ; Rhinitis, Allergic

OBJECTIVEAquaporin (AQP) is a group of cell membrane transporting proteins. The study was designed to investigate the changes of AQP1 and AQP5 in the lung tissue under hyperoxia and their roles in pulmonary edema.

METHODSTwo hundred newborn rats were randomized into different oxygen concentrations exposure: FiO2=0.80 (Experimental group 1), FiO2=0.60 (Experimental group 2), FiO2=0.40 (Experimental group 3) and FiO2=0.21 (Air control group). Rats were sacrificed at 1, 3, 5, 7 and 14 days after the beginning of experiment (10 rats each time point). The expressions of AQP1 and AQP5 were examined by Western Blot. The ratio of lung wet weight to lung dry weight (wet-to-dry weight ratio, W/D), and the protein content in bronchoalveolar lavage fluid (BALF) were measured.

RESULTSCompared with the Air control group, the W/D ratio and the protein content in BALF in the three experiment groups increased significantly and the increased extent was positively related to the duration and the oxygen concentration of hyperoxia-exposure. The expression of AQP1 in the experimental groups began to decrease at the 3rd day and significant differences were found at the 5th and the 7th days after hyperoxia-exposure compared with that in the Air control group (P < 0.05). The AQP1 expression was restored somewhat at the 14th day after hyperoxia-exposure, but it was still lower in the Experimental groups 1 and 2 than that in the Air control group (P < 0.05). The expression of AQP5 in the experimental groups were reduced compared with that in the Air control group 3 days after hyperoxia-exposure and the decrease of AQP5 expression was associated with duration of hyperoxia-exposure. The comparison among three experimental groups showed that the decrease of AQP1 and AQP5 expressions was associated with the concentration of hyperoxia-exposure.

CONCLUSIONSThe expressions of AQP1 and AQP5 decreased in hyperoxia-induced lung injury and correlated with the severity of pulmonary edema.

Animals ; Aquaporin 1 ; analysis ; Aquaporin 5 ; analysis ; Bronchoalveolar Lavage Fluid ; chemistry ; Female ; Hyperoxia ; metabolism ; Lung ; chemistry ; Male ; Pulmonary Edema ; etiology ; Rats ; Rats, Wistar

OBJECTIVETo determine if aquaporin1 (AQP1) and aquaporin5 (AQP5) are expressed in the alveolar capillary membrane in rats. Moreover, to investigate the alteration of AQP1 and AQP5 in acute injured lungs.

METHODSThe distribution of AQP1 and AQP5 in alveolar capillary membrane were investigated by immunohistochemistry and immunoelectron microscopy with affinity-purified antibodies to human AQP1 and AQP5. To study the possibility that alveolar capillary membrane AQP1 and AQP5 undergo altered regulation, we established a rat model using alveolar instillation of lipopolysaccharide (LPS).

RESULTSImmunolabelling showed AQP1 was stained primarily in the microvascular endotheli a of normal lungs, while AQP5 was expressed in type I pneumocytes. Immunohisto chemical analysis showed a significant decrease in the expression of AQP1 and AQP5 in injured lungs at 4h-48h after LPS instillation. AQP1 protein was resumed partly at 24h after LPS instillation and steroid administration, whereas AQP5 was unchanged.

CONCLUSIONThe decreased expressions of AQP1 and AQP5 in injured lungs suggest that both of them may play a role in abnormal fluid transportation.

Animals ; Aquaporin 1 ; Aquaporin 5 ; Aquaporins ; analysis ; Immunohistochemistry ; Lipopolysaccharides ; toxicity ; Lung ; metabolism ; Male ; Membrane Proteins ; Microscopy, Immunoelectron ; Rats ; Rats, Sprague-Dawley ; Respiratory Distress Syndrome, Adult ; metabolism ; pathology

PURPOSE: To evaluate the effect of X-ray irradiation on apoptosis and change of expression of aquaporin 5 (AQP5) and transforming growth factor-beta(TGF-beta) in the rat submandibular gland (SMG). MATERIALS AND METHODS: SMGs of 120 male Sprague-Dawley rats were irradiated with a single X-ray dose (3, 10, 20, or 30 Gy). At the early and late post-irradiation phase, apoptosis was measured by the terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) method, and expression of AQP5 and TGF-beta was determined by immunohistochemical staining. RESULTS: At the late post-irradiation phase, increased apoptosis was evident and marked decreases of expression of AQP5 expression by acinar cells and TGF-beta expression by ductal cells were evident. CONCLUSION: Apoptosis after X-ray irradiation develops relatively late in rat SMG. Irradiation reduces AQP5 and TGF-beta expression in different SMG cell types.
Acinar Cells ; Animals ; Apoptosis ; Aquaporin 5 ; DNA Nucleotidylexotransferase ; Humans ; Male ; Rats ; Rats, Sprague-Dawley ; Submandibular Gland ; Transforming Growth Factor beta

Alcohol intake is known to affect various organs in the human body, causing reduction of salivation in the oral cavity. Hypo-salivation effect of alcohol is a common feature, but the mechanism in salivary glands is still poorly studied. Therefore, in this study, the changes in salivary secretion and water channel protein (aquaporin5, AQP5) in salivary glands of mice were investigated after ethanol administration. Animals were divided in to 4 groups with the control, 4 g/kg ethanol, 8 g/kg ethanol and 16 g/kg ethanol administration groups. One hour after ethanol administration, saliva was collected from the oral cavity, and the animals were killed and parotid and submandibular glands were extracted to analyze the histopathology, AQP5 immunihistochemistry and AQP5 protein level. According to the results, the salivation rate decreased irrespective of the ethanol dose in mice, and viscosities increased with increase in ethanol dose. However, there were no pathological changes in parotid and submandibular glands due to ethanol administration. Expression of AQP5 in parotid and submandibular glands decreased with increase ethanol administration These results indicate that the reduction of salivary secretion due to acute alcohol intake is closely related to decrease of the water channel protein such as AQP5 in parotid glands and submandibular glands, rather than the damage of salivary glands.
Animals ; Aquaporin 5 ; Eating ; Ethanol ; Human Body ; Mice ; Mouth ; Parotid Gland ; Saliva ; Salivary Glands ; Salivation ; Submandibular Gland ; Viscosity ; Water

OBJECTIVETo study the estrogen-like action mechanism of Menoprogen on ovariectomized female rats.

METHODOvariectomized rat model (OVX) was established and estradiol (17beta-estradiol, E2) was used as positive control. The uterine coefficient and serum E2 level were determined after administration of Menoprogen for 2 weeks. The uterine vascular endothelial growth factor (VEGF), water channel protein (aquaporin, AQP), estrogen receptor (ER), progesterone receptor (PR) and the expression of proto-oncogenes (c-jun, c-fos) were observed by immunohistochemical method. Yeast two-hybrid assay was applied to detect the existence of components combining with ERalpha or ERbeta in Menoprogen.

RESULTBoth Menoprogen and E2 could significantly elevate the uterine coefficient of OVX rats, increase the level of serum E2 and up-regulate the expressions of VEGF, AQP2 as well as AQP5 in uterus. E2, not as E2 Menoprogen couldn't promote the expressions of ERalpha, PR, c-jun and c-fos in OVX rat uterus. And yeast two-hybrid assay showed no components combining with ERalpha or ERbeta in Menoprogen.

CONCLUSIONMenoprogen has estrogen-like effect, and can be used to treat menopause syndrome. The risk of estrogen-mediated endometrial cancer is low for this treatment because its mechanism is different from estrogen-like substances.

Animals ; Aquaporin 2 ; metabolism ; Aquaporin 5 ; metabolism ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Estradiol ; blood ; Estrogen Receptor alpha ; metabolism ; Estrogens ; pharmacology ; Female ; Ovariectomy ; adverse effects ; Rats ; Rats, Wistar ; Receptors, Progesterone ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism

OBJECTIVETo explore the protective mechanism of Nervilia fordii (NF) by observing the effect of its pretreatment on lung aquaporin 1 and 5 (AQP-1, AQP-5) expression in rats with endotoxin-induced acute lung injury (ALI).

METHODSTwenty-four SD rats were randomly divided into 3 groups, the normal group (A), the NF pre-intervention group (B) and the endotoxin model group (C). Rats in Group B and C were made into ALI by endotoxin (5 mg/kg) injection via sublingual vein, and NF pretreatment was applied to Group B. Animals were sacrificed at the 8 h after modeling, their lung were taken for observing the water permeability change by wet/dry weight ratio (W/D) measuring, pathological feature by HE staining, and the expression of AQP-1, AQP-5 was detected by immunohistochemistry and RT-PCR.

RESULTSThe W/D ratio of lung was higher in model rats than in normal rats, but as compared with Group C, it was significantly lower (P < 0.05) in Group B. The pulmonary edematous change was significantly mild and the AQP-1 and AQP-5 protein expressions were significantly higher in Group B than in Group C (P < 0.05).

CONCLUSIONNF pretreatment can promote lung AQP-1 and AQP-5 expression up-regulation, increase lung water clearance and transportation to improve the water balance and eliminate pulmonary edema, so as to effectively protect lung from acute injury.

Acute Lung Injury ; chemically induced ; drug therapy ; prevention & control ; Animals ; Aquaporin 1 ; metabolism ; Aquaporin 5 ; metabolism ; Drugs, Chinese Herbal ; therapeutic use ; Endotoxins ; Female ; Lung ; metabolism ; Male ; Phytotherapy ; Rats ; Rats, Sprague-Dawley ; Up-Regulation

A role of nitric oxide (NO) in the regulation of sodium transporters and water channels in the salivary gland was investigated. Male Sprague-Dawley rats were treated with NG-nitro-L-arginine methyl ester (L- NAME, 100 mg/L drinking water) for 1 week. The control group was supplied with normal tap water. The expression of Na+,K+-ATPase, type 2 Na+/K+/2Cl- cotransporter (NKCC2), type 1 Na+/H+ exchanger (NHE1), alpha-subunit of epithelial sodium transporter (ENaC), and aquaporin-5 (AQP5) and aquaporin-1 (AQP1) proteins were determined in the submandibular gland by Western blot analysis. Following the treatment with L-NAME, the expression of Na+,K+-ATPase alpha1-subunit, NKCC2, NHE1, and ENaC alpha- subunit increased significantly. On the contrary, the expression of AQP5 was significantly decreased, while that of AQP1 was not significantly altered. These findings indicate that the sodium transporters and water channels may be under a tonic regulatory influence of NO in the salivary gland.
Animals ; Aquaporin 5 ; Aquaporins ; Blotting, Western ; Drinking ; Humans ; Male ; NG-Nitroarginine Methyl Ester ; Nitric Oxide ; Proteins ; Rats ; Rats, Sprague-Dawley ; Salivary Glands ; Sodium ; Submandibular Gland ; Water