Absorption through the Nasal Mucosa of Tannic-Acid Treated Mice

Abstract

Reports have been given of the absorption of Prussian blue through the nasal mucosa of rabbits 1 and mice. 2 , 3 A study by Olitsky and Cox 2 of the absorption of the pigment 1 to 3 hours after its instillation in mice previously treated intranasally with tannic-acid shows that absorption at this time is less evident than in untreated mice. Subsequently Rake 3 demonstrated that absorption through the nasal mucosa, chiefly the olfactory, is very rapid and has reached its maximum in mice killed at 2 minutes; furthermore, that much of the absorption occurs by way of the olfactory sensory cells. It seemed advisable to study the absorption of Prussian blue from the nasal cavities of tannic-acid treated mice during these early periods.

Nine Swiss mice each received eight preliminary intranasal instillations over 3 days. Each dose, consisting of 0.03 cc. of 0.8 percent tannic-acid in 1% glycerine, was dropped on the outside of the nostrils from whence it was gradually breathed into the nose. Four hours after the last dose each mouse received 0.02 cc. of a mixture of equal parts of 10% iron ammonium citrate and 10% potassium ferrocyanide intranasally by the same technique. Two minutes after commencement of intranasal inoculation 5 mice were sacrificed by decapitation and 13 minutes later the other 4 were so sacrificed. Fixation, sectioning, and staining with Mayer's carmine were carried out as indicated elsewhere. 3 A few sections were stained with hematoxylin and eosin to facilitate study of the inflammation.

Following intranasal treatment with tannic-acid as given above, it is very rarely that any mouse shows exudate from the nostrils. Nevertheless, it was found in the present study that there is to be observed, microscopically, marked exudate into the nasal cavity, especially over the olfactory mucosa and around the turbinates. This exudate is composed of mucus, leucocytes—chiefly polymorphonuclears—and some red cells. The olfactory mucosa and submucosa show swelling and infiltration with oedema fluid and leucocytes. The capillaries of the submucosa are dilated and contain many polymorphonuclear leucocytes. Changes in the respiratory mucosa are slight. Six mice show intense inflammation. In 3 the inflammation is less. Preliminary treatment with 1% tannic acid in normal saline, instead of 0.8% in 1% glycerine, is found to produce similar inflammatory changes.