[A biochemical and cytological explanation of cochlear otospongiosis].

Carrying on their study about the enzymatic activity of the otospongiotic micro-foci and the hydrolytic activity of the perilymph, the authors present their work concerning the value of trypsin and alpha-1-anti-trypsin in the perilymph of otospongiotic patients operated on by stapedectomy. They describe the method used and give the obtained results which permit to believe that the values of trypsin, and a contrario of anti-trypsin, appear to constitute an index of the severity of the progression. Moreover, the authors have investigated the eventual toxic action of various trypsin concentrations on the hair cells of the Corti organ in the guinea-pig. This study has been carried through successfully by means of the electron microscopic scanning method which allows to obtain an "electron cochleogramme in situ". They explain the method and come to the conclusion that the intensity and extension of the Corti hair cells alterations in a cochlea receiving a perfusion with trypsin solutions, are tightly related to the trypsin concentration. However, they do not pretend so far that these results reflect exactly the anatomo-pathologic reality during the slow progression of otospongiosis towards cochlear deterioration. These two series of experimentation appear to confirm their enzymatic concept of otospongiosis: the long, slow and extremely capricious progression of the disease is the duplicate of its cytologic progression, the contact between hydroltic enzymes and Corti cells having the same capricious character. These findings perfectly corroborate the previus ones they made in this field, as well as the correlations they have established between hydrolytic activity of the perilymph and audiometric progression. Consequently, they believe that the mechanism of the otospongiotic disease is provoked by the rupture of the balance trypsin/anti-trypsin in the otospongiotic micro-foci and thus in the inner ear fluids.