Fig. 2

Macroscopic, histological, and immunohistochemical treatment results of 2-mm circular meniscus defects in the avascular zone with meniscus cell-scaffold composites (a–h) and MSC-scaffold composites (i–p). In both groups (each n = 6), successful meniscus regeneration with differentiated repair tissue could be detected after 3 months in vivo. Most of the treated menisci show promising treatment results (images a–d, best results after meniscus cell treatment; i–l, best results after MSC treatment) with completely integrated meniscus-like regenerated tissue (e–h and m–p show the worst results of each group). Scale bars: a,e,i,m = 4 mm, b,d,f,h,j,l,n,p = 0.5 mm, c,g,k,o = 0.1 mm). a,e,i,m Macroscopic view of menisci on the tibia plateau with filled circular defects after 3 months; c,g,k,o Higher magnification of the integration zones of images b,f,j,n. d,h,l,p Collagen type II immunostaining