Alteration of extracellular collagen matrix in the myocardium of canines infected with Dirofilaria immitis.
The heart consists of cardiocytes and the interstitial extracellular matrix (ECM), which is made up mainly of collagens. The ECM has been suggested to be important in maintaining the structure and function of the heart. This investigation attempted to elucidate the changes in the ECM collagens in the hearts of canines with dirofilariasis. The ECM collagen fibrils of the heart are grouped into endomysial struts, epimysial weaves, and perimysial coils. In the present study, we used the modified silver impregnation technique to stain paraffin-embedded sections to demonstrate three types of ECM. The results revealed that the ECM content of the heart was significantly reduced in heartworm-infected dogs, and became fragmented and dissociated. In addition, the amounts of collagen in the septum (Sep), RVs and LVs in canines with dirofilariasis (Sep=11.55+/-0.65, RV=12.07+/-0.59, LV=11.72+/-0.62 microg/mg, n=24) were significantly lower (p<0.01) than that in the normal canines (Sep=15.09+/-0.72, RV=15.16+/-0.83, LV=14.91+/-0.89 microg/mg, n=8). These results indicated that heartworm infection induced the remodeling of the extracellular matrix, thus markedly altering the architecture and function of the heart.
Wang
Jiunn-Shiow
JS
Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan.
Tung
Kwong-Chung
KC
Huang
Chiu-Chen
CC
Lai
Cheng-Hung
CH
D000818:Animals; D003094:Collagen / Q000378:metabolism*; D004183:Dirofilaria immitis / Q000254:growth & development*; D004184:Dirofilariasis / Q000378:metabolism* / Q000469:parasitology; D004283:Dog Diseases / Q000378:metabolism / Q000469:parasitology* / Q000473:pathology; D004285:Dogs; D005109:Extracellular Matrix / Q000378:metabolism* / Q000469:parasitology / Q000648:ultrastructure; D006321:Heart / Q000469:parasitology*; D006651:Histocytochemistry / Q000662:veterinary; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure
D003094:Collagen