A confocal laser scanning microscope (LSM 900, Zeiss, Oberkochen, Germany) was used to image the fluorescence from PSR-stained and collagen I antibody-labeled inserts. A 561 nm laser was used to excite the PSR-stained sample with a detection band of 613-700 nm. A 488 nm laser was used to excite the CoraLite 488 fluorophore conjugated to the Collagen I antibody with a detection band of 505-550 nm. A 63x objective (oil immersion) was used for both the PSR and CoraLite 488 imaging.