Histology of Cruciate Ligament Rupture 53(A)3500
3000Epiligamentous region
Core regionEpiligamentous region
Core region25002000
15001000
500140120100
806040
2000
Young - Intact
dogs- Intact
Groupa,lla,lla,lA,IA,IA,I
A,I A,IA,Ia,b,ll
b,llb,llAged Ruptured
dogsYoung - Intact
dogs- Intact
GroupAged Ruptured
dogsTotal cell density (#/mm2 )Non viable LDH- cell density (#/mm
2 )(B)Figure 6.7 Relationship of total cell number densities to
CrCL disease status in the epiligamentous and core
regions of the CrCL (A), and relationship of non-viable
LDH–cell densities to CrCL disease status in the
epiligamentous and core regions of the CrCL (B).
Columns within a region with differing upper- or
lower-case letters are significantly different (P<0.05).
Columns within a CrCL status group with differing Roman
numerals are significantly different. Source: Hayashiet al.
2003b. Reproduced with permission from the American
Veterinary Medical Association.
fibrocartilaginous transformation may predis-
pose CrCL to pathological rupture.
Areas of fibrocartilage are also observed,
however, in grossly normal CrCL in low-
risk breeds (Greyhounds), when intrinsic ECM
changes in the CrCLs of Labrador Retriever
(high-risk breed) are compared with those in
Greyhounds (Comerfordet al. 2006). Transmis-
sion electron microscopy revealed that the col-
lagen fibril diameters of Greyhound CrCL were
larger than those of Labrador Retrievers, which
may relate to tissue maturity and the tissue’s
mechanical properties. Histology revealed the
(A)(B)(C)Figure 6.8 Immunohistochemical staining for factor VIII
in the core region of intact (A) and ruptured (B) canine
cranial cruciate ligaments, and the torn end of ruptured
canine cruciate ligament (C). Scale bars= 50 μm. Positive
red staining can be identified in the lumen of vascular
structures. Source: Hayashiet al. 2011b. Reproduced
with permission from John Wiley & Sons, Inc.