Figure 2

Histopathological analysis. BALB/c mice were intranasally exposed to nSP30, nSP70, mSP300, nSP100, or mSP1000 at a concentration of 500 μg/mouse for 7 days. Twenty-four hours after the final administration, nasal cavity (a,d,g,j,m,p), liver (b,e,h,k,n,q) and brain (c,f,i,l,o,r) tissue samples were stained with hematoxylin–eosin. In images, solid line delineates cell aggregation. The histopathological grades of these samples are summarized in Table 1.