Fig. 3

Differences of bone remodelling activities between younger and older male BALB/c nude mice. a The trabecular bone content (BV/TV) was compared between 6-week old (Young) or 16-week old (Mature) male mice using micro-CT analysis. n > 9. b The trabecular bone mass difference can be clearly seen on the cross-section micro-CT image 250 μm below the growth plate, scale bar = 500μm. c The bone formation marker (P1NP) and d bone resorption marker (TRAP) were also measured in mouse serum sample using ELISA kits, n > 9. e The bone resorbing osteoclasts (TRAP staining +, marked by black arrow heads) and bone forming osteoblasts (marked by small black arrows) were viewed and quantified on the endocortical bone surface of 6- and 16-week old mice tibiae after sectioning and TRAP staining. Scale bar = 50μm. f The number of osteoblasts per mm endocortical bone surface (N. Ob/B.Pm), g bone surface covered by osteoblasts (Ob.Pm/B.Pm), h number of osteoclasts per mm endocortical bone surface (N.Oc/B.Pm), and i bone surface covered by osteoclasts (Oc.Pm/B.Pm) were all compared between 6- and 16-week old mice. n > 4, * P < 0.05, ** P < 0.01, **** P < 0.0001, t-test