Luffa operculata effects on the epithelium of frog palate: histological features

Abstract

Luffa operculata is the botanical name of buchinha-do-norte or cabacinha, which is a medicinal plant widely used for the treatment of rhinitis and rhinosinusitis. In Europe and USA, it is available in homeopathic medicines. In Brazil, Luffa operculata dry fruit infusion is inhaled or instilled into the nose releasing profuse mucous secretion, thus relieving nasal symptoms. Nevertheless, this often may cause irritation, epistaxis or anosmia.

Study design: Experimental.

Material and method: The effects of Luffa operculata were evaluated in different concentration infusions, in isolated frog palate preparation, testing 46 palates after immersion. Four groups (n = 10) were tested with the infusion prepared with frog Ringer (isotonic): control; 60 mg/L; 600 mg/L; and 1200 mg/L. An additional group was tested using the infusion with water (600 mg/L H2O, n = 6). Epithelial samples were harvested to be studied under light microscopy and electron transmission microscopy.

Results: In treated palates, light microscopy findings were dose-dependent standard toxic changes. Electron transmission microscopy showed enlargement of intercellular spaces and tight junctions disruption, pointing to ion-fluid transport abnormalities.

Conclusions: Luffa operculata infusion in currently used doses can promote significant structural and ultrastructural changes in the epithelium of this ex vivo model of respiratory mucosa.

Figure 1

Dry fruit of Luffa operculata, transversal (a) and longitudinal (b) sections. The detail shows the fibrous mesocarpus and the seeds.

Figure 2

Slide with frog palate epithelium from group 1 showing normal aspect: mucous layer in contact with preserved epithelial surface and lamina propria (light microscopy, PAS-AB staining, 100 times magnified).

Figure 3

Slide with frog palate epithelium from group 1 showing details of lamina propria glands (light microscopy, PAS-AB staining, 400 times magnified).

Figure 4

Slide with frog palate epithelium from group 1 showing cilia at transversal section and mucous contained in mucous cell (transmission electron microscopy, 800 times magnified).

Figure 5

Slide with frog palate epithelium from group 1 showing cilia at longitudinal section and preserved tight junction (arrow) between two contiguous cells (transmission electron microscopy, 20,000 times magnified)

Figure 6

Slide with frog palate epithelium from group 1 showing details of desmosome, surrounded by intermediate filaments of cytokeratin (transmission electron microscopy, 800 times magnified).

Figure 7

Slide with frog palate epithelium from group 5 showing disorganization of epithelium and increase in volume of extruded mucus (light microscopy, PAS-AB staining, 100 times magnified)

Figure 8

Slide with frog palate epithelium from group 4 showing epithelial destruction, cell vacuolization and increase in intercellular space (light microscopy, PAS-AB staining, 400 times magnified).

Figure 9

Slide with frog palate epithelium from group 4 showing epithelial disorganization, cell edema and complete extrusion of mucus (light microscopy, PAS-AB staining, 400 times magnified).

Figure 10

Slide with frog palate epithelium from group 5 showing increase in intercellular space and presence of intercellular junctions: desmosomes (red arrow) and tight junction (blue arrow). The increase in transit of fluid to extracellular matter is morphological evidence of increase in permeability of epithelial barrier (transmission electron microscopy, 10,000 times magnified).

Figure 11

Slide with frog palate epithelium from group 5 showing detail of the slide above, showing two desmosomes and increase in intercellular space with fluid material containing proteins (flocculation) (transmission electron microscopy, 40,000 times magnified).