Fig. 3.

The study design, macroscopic observation, histological analysis and representative immunohistochemical staining 8 weeks after cell transplantation. a Rabbit knee joint meniscus defect model. A cylindrical defect with a diameter of 1.5 mm was formed at the anterior corner of the medial meniscus. Black arrows indicate the defect. b Experimental design and schematic diagram of animal distribution in each group. Dead rabbits were excluded from any analysis. IHC, immunohistochemistry. c The macroscopic images of meniscus repair after injury at week 8. Scale bar: 2 mm. And macroscopic score for the general view of meniscus repair at week 8, n = 9 in each group. P values, two-tailed Mann-Whitney tests. d HE staining of meniscus repair at week 8. Green arrowhead shows mature chondroid cells. Scale bar: 2.5 mm, 500 μm, 100 μm. e Safranin-O staining (SO). f Masson staining. Black arrows show chondrocytes in isogenous group. g Type I collagen (Col-1). h Type II collagen (Col-2). For (e)–(h), scale bar: 2.5 mm, 500 μm, 50 μm. The boxed areas are shown at higher magnification. i Semi-quantitative analyses of immunohistochemical staining for Col-1 and Col-2. P values, two-tailed independent sample t-test. j shows the result of Pauli’s score at week 8, n = 7 in each group. P values, two-tailed independent sample t-test. *P < 0.05, **P < 0.01; Data are presented as mean ± SEM