Effect of hypo-, iso- and hypertonic saline irrigation on secretory mucins
and morphology of cultured human nasal epithelial cells

Abstract
Conclusion. We speculate that isotonic saline is the most physiological
irrigation solution in terms of mucus secretion and the cellular morphology
of nasal epithelial cells. Objective. To determine the most physiologic and
effective saline concentration for nasal irrigation in terms of mucus
secretion and cellular morphology by using normal human nasal epithelial
cells treated with hypo-, iso- and hypertonic saline. Material and methods.
Fully differentiated passage-2 normal human nasal epithelial cells were
treated with pure water and with 0.3% (hypotonic), 0.9% (isotonic) and 3%
(hypertonic) saline solutions. mRNA expression levels of MUC5AC and MUC5B,
which are known to be major airway mucins, were analyzed after 30 min using
reverse transcriptase polymerase chain reaction. Total mucin and MUC5AC and
MUC5B mucin secretions were analyzed using dot-blotting. Cellular morphology
was observed with light microscopy after hematoxylin-eosin staining and with
scanning electron microscopy. Results. MUC5AC and MUC5B mRNA levels did not
change after treatment with pure water and various concentrations of saline.
Total mucin and MUC5AC mucin secretions only increased following pure water
treatment, while MUC5B mucin secretion increased with pure water, hypo- and
hypertonic saline treatment. Morphologic analysis revealed that pure water
severely damaged normal human nasal epithelial cells and that only isotonic
saline did not affect their morphology.

I would guess that if the nose is swollen so one can't breathe, then
hypertonic would be best.
If one wants only to clean out dust or mold etc. then isotonic or Locke
Ringer's would be best.

Hypotonic should only be used to hydrate a very dry nose condition.
Pure water alone should be avoided.
In retrospect, isotonic is the best and least damaging when not wanting to
spend the funds for Locke Ringer's solution.

Jamffer