Bullfrog Palate Research Articles

The Effects of Electronic Cigarette (ECIG)-Generated Aerosol and Conventional Cigarette Smoke on the Mucociliary Transport Velocity (MTV) Using the Bullfrog (R. catesbiana) Palate Paradigm.

Background: While ECIGs are under scrutiny concerning safety, particularly in reference to the physiological impact that aerosolized ECIG liquid (E-liquid) may have on respiratory tissues, others believe that ECIGs are a “Harm Reduction” alternative to conventional cigarettes. Previous studies investigating ciliated respiratory epithelium indicate that smoking shortens cilia length, reduces cilia beat frequency and disrupts respiratory epithelium, which most likely contributes to the inhibition of mucocilliary clearance. Monitoring mucous clearance of respiratory tissues exposed to ECIG-generated aerosol or conventional cigarette smoke, as indexed by mucous transport velocity (MTV), is one way to gauge the impact aerosol and smoke have on the respiratory tract. Therefore, we designed an experiment to test the effect of ECIG-generated aerosol and smoke on MTV using the frog palate paradigm.Methods: Peristaltic pumps transport ECIG-generated aerosol and conventional cigarette smoke into custom-made chambers containing excised bullfrog palates. MTVs were determined before exposure, immediately after exposure and approximately 1 day following exposure. MTVs were also determined (at the same time points) for palates exposed to air (control). Surface and cross sectional SEM images of palates from all three groups were obtained to support MTV data.Results: The results indicate that ECIG-generated aerosol has a modest inhibitory effect (p < 0.05) on MTV 1 day post-exposure (0.09 ± 0.01) compared to control MTV (0.16 ± 0.03 mm/s). In contrast, smoke completely inhibits MTV from 0.14 ± 0.03 mm/s immediately before exposure to 0.00 mm/sec immediately after exposure and the MTV is unable to recover 1 day later. SEM images of control palates and palates exposed to ECIG-generated aerosol both show cilia throughout their epithelial surface, while some areas of palates exposed to smoke are completely devoid of cilia. Additionally, the epithelial thickness of aerosol-exposed palates appears thicker than control palates while smoke-exposed palates appear to be thinner due to epithelial disruption.Conclusions: These results indicate that ECIG-generated aerosol has only a modest effect on mucocilary clearance of bullfrog palates and aerosol sedimentation accounts for epithelial thickening. In accordance with the primary literature, conventional cigarette smoke dramatically inhibits mucociliary clearance and is, in part, due to decreased number of cilia and disruption of the smoke-exposed epithelium.

CYCLOSPORIN A REDUCES AIRWAY MUCUS SECRETION AND MUCOCILIARY CLEARANCE IN RATS

To assay the effects of cyclosporin A on mucus secretion from goblet cells and on mucociliary transport in situ in rats. Twenty-one male Wistar rats were assigned to 3 groups: control (n = 5), saline (n = 8), and cyclosporin A (n = 8). After 30 days of drug therapy, the rats were killed, and the lungs were removed from the thoracic cavity. Mucus samples were collected, and the transport rate was evaluated in vitro using a bullfrog palate model. Mucociliary transport was timed in situ by direct view of particles trapped on the mucus moving across the respiratory tract. Finally, the amount of stored mucins in the goblet cells of the respiratory epithelium was measured. Drug dosage measurements showed that cyclosporine blood concentration at the moment the rats were killed was 1246.57 +/- 563.88 ng/mL. The in vitro transport rate was significantly lower (P < .001) in the cyclosporin A-treated group. Also, the in-situ mucociliary transport rate was decreased in all cyclosporin A-treated animals when compared to the saline group (P = .02). Mucus quantity measurements showed a significant decrease on both acid (P = .01) and neutral (P = .02) mucus production from goblet cells in the animals submitted to cyclosporin A therapy. The correlation between the percentage of total mucus and in vitro transport rate was positive and significant (r = 0.706, P < .001), as was the correlation between the percentage of total mucus and the in situ mucociliary transport rate (r = 0.688, P = .001). This study shows that cyclosporin A plays an important role in the impairment of the mucociliary clearance in rats by reducing both acid and neutral mucus production from goblet cells and causing a decrease in the mucociliary transport velocity.

Ophiopogon root ( Radix Ophiopogonis) prevents ultra-structural damage by SO 2 in an epithelial injury model for studies of mucociliary transport

We studied the action of the herb, Ophiopogon root (OR) in a epithelial injury model, hypothesizing that it may have beneficial effects on mucociliary transport following injury to the palate induced by sodium metabisulphite (MB) which releases SO 2 on contact with water. OR (extract from 1g of root/ml)-incubated palates and non–incubated palates were compared to assess the effect of MB on mucociliary clearance on the bull frog palate. MB 10 −1 M, acutely increased mucociliary clearance time (MCT) by 254.5 ± 57.3% in untreated and 243.3 ± 98.5% in OR-incubated palates, (over all significance assessed by one-way ANOVA, F = 12.82, p < 0.001, df = 8,54 for MB and F = 10.56, p < 0.001, df = 8,54 for OR). MCT returned to normal during recovery in OR-treated palates following MB. In untreated palates, MCT did not return to control values during a similar recovery period. ANOVA comparing MCTs in the recovery period in untreated vs OR-treated palates was significantly different (F = 2.92, p < 0.03, df = 5,36). SEM images of epithelial tissue, analyzed by morphometry, showed a 25 ± 12% loss of ciliated cells in untreated palates and little or no damage to cilia in OR-treated palates. Intact groups of ciliated cells were found in SEM micrographs of mucus from MB-treated palates. We conclude that the loss of cilia or ciliated cells prevented full recovery of MCT after MB in untreated palates. In OR-incubated palates, mucociliary transport was completely restored within 20 min after topical application of MB, possibly through a protective action on the extra-cellular matrix.

The transport of polymeric microspheres across the ciliated epithelia of the bullfrog

The influence of some hydrophilic polymers on the clearance of particles across the ciliated epithelium of the bullfrog palate has been examined. The polymers studied were Carbopol 907 cross-linked with maltose to provide microspheres of varying cross-link density, Carbopol 934P, hydroxypropylmethylcellulose, chitosan and poly(vinyl alcohol). Transport rates were determined relative to glass spheres. The polymers in dilute solution (0.1 and 0.5% w/v) resulted in a reduction in the transport rate of the glass spheres. For non-cross-linked microspheres, Carbopol 934P exhibited a lower transport rate than the more slowly hydrating chitosan. The cross-linked poly(acrylic acid) microspheres showed clearance rates which were dependent on the cross-link density. Incorporation of some preservatives (EDTA, methylhydroxybenzoate, chlorbutol and chlorocresol), known to reversibly retard clearance, into the cross-linked poly(acrylic acid) microspheres produced effects dependent on cross-link density: lightly cross-linked microspheres were cleared more slowly than the preservative-free microspheres whilst for more heavily cross-linked particles the converse was observed.

Effect of Lipopolysaccharide of Haemophilus influenzae on Ciliary Activity of the Human Nasal Mucosa and Bullfrog Palate Clearance

The influence of lipopolysaccharide (LPS) of Haemophilus influenzae on the ciliary activity of human nasal mucosa was first studied using both a photo-oscillographic apparatus and by bullfrog palate clearance. Neither modification of cilialy activity nor change in bullfrog palate clearance was observed in the early phase after the administration of LPS.

Effect of Lipopolysaccharide of Haemophilus influenzae on Ciliary Activity of the Human Nasal Mucosa and Bullfrog Palate Clearance

AbstractThe influence of lipopolysaccharide (LPS) of Haemophilus influenzae on the ciliary activity of human nasal mucosa was first studied using both a photo-oscillographic apparatus and by bullfrog palate clearance. Neither modification of cilialy activity nor change in bullfrog palate clearance was observed in the early phase after the administration of LPS.Key Words: ciliary heat frequencymucociliary transport rate

Role of mucus and cilia on dysfunction in nasal mucociliary transportation in chronic sinusitis

Decelerated nasal mucociliary clearance has been demonstrated in patients with chronic sinusitis. However, it is as yet known whether this depression in mucociliary clearance is related to changes in the rheological properties of mucus, in the number and function of the cilia, or other factors. The purpose of this study was to determine if abnormal rheological properties of mucus or decrease of number of cilia contribute to the mucociliary dysfunction in chronic sinusitis.Nasal mucus was collected from 38 patients with chronic sinusitis and then, nasal mucociliary clearance (ST) was determined by saccharin granule technique. ST of the 16 patients was within normal range and ST of the other 22 patients was decelerated. Mucociliary transport rate of the nasal mucus on mucus depleted bullfrog palate was 5.93±1.04 mm/min in the patients whose ST was normal, and was 5.54±1.94 mm/min in the patients whose ST was decelerated. Significant difference in the mucociliary transport rate on frog palate was not observed between these two groups. This result suggests that rheological properties may not contribute to the slowing of nasal mucociliary clearance.The quantitative scanning electron microscopic study was performed on both nasal turbinate and maxillary sinus mucosae of 14 coupled samples. The epithelial surface occupied by cilia was determined using an image analyzer. The ciliated area of the epithelium was 90.2±9.9% in the nasal turbinate and 54.4±35.1% in the maxillary sinus mucosa from the patients undergone radical surgery. Cilia were not injured in the nasal cavity and were injured in the maxillary sinus in various degrees. This result shows that the slowing of nasal mucociliary clearance is not due to the decrease of the number of cilia.There was no decrease in the number of cilia in the nasal cavity in patients with chronic sinusitis. Rheological properties of nasal mucus are not the cause of the impairment of nasal mucociliary clearance in this disease. In conclusion, other factors such as tethering between outer mucous layer and mucus secreting cells and/or decrease of the thickness of periciliary fluid layer may play a major role for the deceleration of nasal mucociliary clearance associated with chronic sinusitis.

Mucociliary clearance in chronic sinusitis: related human nasal clearance and in vitro bullfrog palate clearance.

Nasal mucociliary clearance was measured in both healthy subjects and patients with chronic sinusitis using saccharin granule technique. Nasal mucociliary transit time (ST) was significantly slower in the patients with chronic sinusitis compared with that in controls (p less than 0.005). Nasal mucus collected from each nasal cavity was used for in vitro bullfrog palate clearance studies and compared to the in vivo nasal ST. Mucociliary clearance rate (MTR) on frog palate was 12.5 +/- 2.5 mm/min in the mucus from control subjects, 6.1 +/- 1.5 mm/min in the mucus from the patients. The difference was statistically significant (p less than 0.005). The MTR on frog palate in the patients whose nasal ST was within normal range was significantly slower than that in controls (p less than 0.005), but not significantly different from that in the patients whose nasal ST was over the normal range. These results suggest that the nasal mucous properties which decreased the mucociliary clearance on frog palate did not contribute to the mucociliary clearance of the patients who had a normal one. No significant correlation existed between MTR on frog palate and nasal ST in both control and chronic sinusitis. In chronic sinusitis patients, decelerated nasal ST was recovered significantly by normal saline nebulization compared with the value before the nebulization (p less than 0.01). None of the significant change of ST was observed in control before and after the nebulization.

Effect of nondialyzable solids concentration and viscoelasticity on ciliary transport of tracheal mucus.

The viscoelastic properties of reconstituted canine tracheal mucus were correlated with the ciliary transport rate measured on the bullfrog palate. A maximum in mucociliary transport rate was found at an optimal concentration of nondialyzable solids of 1.5 to 2 per cent. At concentrations less than this value, the mucus had little or no elasticity and low rates of transport; at concentrations greater than the optimum, however, further increases in elastic modulus also resulted in decreasing transport.

Mucus clearance: in vivo canine tracheal vs. in vitro bullfrog palate studies

Tracheal mucociliary clearance was studied by a radioisotope technique in pentothal-anesthetized beagles in the control, atropinized, or dehydrated state. Mucus collected from a tracheal pouch in each dog was used for in vitro bullfrog (Rana cantesbiana) palate clearance studies and compared to the in vivo clearance rates. In all three experimental states, there was a significant correlation between in vivo and in vitro rates, suggesting that tracheal pouch mucus is a good model for investigating the mucociliary flow properties of intact airway mucus. When compared to matched controls, atropine appeared to cause a slowing of the in vivo clearance rate but not of the in vitro rate. Dehydration had no effect on either. The appropriateness of the frog palate method in the study of human respiratory disease (e.g., chronic bronchitis, cystic fibrosis) as well as its potential as an objective method of assessing the effects of various therapeutic modalities in these diseases is discussed.