[Immunohistological investigation of proteoglycans and collagens in experimental facial nerve palsy].

The extracellular matrix (EM) has various important functions. The basement membrane, which is part of the EM, has major components such as type IV collagen (C-IV), laminin, and heparan sulfate proteoglycan (HSPG). The basement membrane controls osmosis of various molecules, as well as the approach of growth factors, hormones, and neurotransmitters, etc. to the cellular surface. Thus, in this study, distributions of HSPG and C-IV and associated changes were investigated immunohistologically using monoclonal antibody against HSPG and polyclonal antibody against C-IV in mice models of experimental facial nerve palsy. In normal tissues, HSPG and C-IV were stained slightly in the basement membrane of the myelin sheath, moderately in the perineurium and slightly in the epineurium of the nerve. In the model of extratemporal facial nerve palsy, these stained components became more apparent, i.e., moderate or stronger, in the basement membrane of the myelin sheath, one week after the experiment. HSPG was perceptibly stained even at a later period of observation, while staining of C-IV became weak in the early period of observation. In the model of intratemporal facial nerve palsy, the staining of HSPG and C-IV of the basement membrane in the myelin sheath, also became more apparent (became moderate) one week after the experiment. But in this model, the degree of staining in the basement membrane was uniformly increased throughout the nerve fascicle. This is a characteristic feature of intratemporal facial nerve palsy, and requires further investigation. These results suggest that the basement membrane may play an important role in facial nerve regeneration, and that HSPG may maintain control over the degree of nerve regeneration.