Figure 5

Transmission electron microscopy of the arrangements of collagen fibres in control and bone samples from 4, 12 and 24 weeks after the onset of diabetes (a–f). Bone specimen from control group at 4 weeks shows tight packing of collagen fibrils (a) and in experimental group (b) shows initiation of ultrastructural changes resulting in debonding of collagen fibrils and formation of linear microcracks (arrows) (c) Bundles of collagen fibrils are arranged in different directions in bone specimens from controls at 12 weeks (d) collagen fibrils forming a meshwork (arrows) enclosing various porosities in bone specimens at 12 weeks of duration of diabetes (e) collagen fibrils and bone matrix are more compact in control animals at 24 weeks (f) completely disorganized arrangement of collagen fibril number and size of afibrillar voids increases in bone specimens from 24 weeks of the duration of diabetes (g) showing microcrack bridging pattern (arrows). The white scale bar is 500 nm for (a–c and e,g) and 1 µm for (d,f).