Differential expression of TNF-alpha, IL-6, and IGF-1 by graded mechanical stress in normal rat myocardium.
An isovolumic normal rat heart Langendorff model was used to examine the effects of moderate (15 mmHg) and severe (35 mmHg) mechanical stretch on the time course (from 0 to 60 min) of myocardial expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and insulin-like growth factor (IGF)-1 and their cognate receptors. After 10 min of moderate stretch, TNF-alpha was de novo expressed, whereas constitutive IL-6 and IGF-1 levels were slightly upregulated; no further changes occurred up to 60 min. In comparison, severe stretch resulted in a higher and progressive increase in TNF-alpha, IL-6, and IGF-1 expression up to 20 min. After 20 min, whereas TNF-alpha expression further increased, IL-6 and IGF-1 levels progressively reduced to values lower than those observed under moderate stretch and in unstretched (5 mmHg) control myocardium (IL-6). Mechanical stretch did not significantly alter the expression of the cognate receptors. Indeed, the TNF-alpha receptor (p55) tended to be progressively upregulated under severe stretch over time. The current data provide the first demonstration that TNF-alpha, IL-6, and IGF-1 ligand-receptor systems are differentially expressed within the normal rat myocardium in response to graded mechanical stretch. Such findings may have potential implications with regard to compensatory hypertrophy and failure.
Palmieri
Emiliano A
EA
Department of Medicina Clinica, Scienze Cardiovascolari ed Immunologiche, L Califano Facoltà di Medcina e Chirurgia, Università degli Studi di Napoli Federico II, Naples, Italy.
Benincasa
Giulio
G
Di Rella
Francesca
F
Casaburi
Cosma
C
Monti
Maria G
MG
De Simone
Giuseppe
G
Chiariotti
Lorenzo
L
Palombini
Lucio
L
Bruni
Carmelo B
CB
Saccà
Luigi
L
Cittadini
Antonio
A
D000818:Animals; D017931:DNA Primers; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D017526:Receptor, IGF Type 1 / Q000235:genetics; D019947:Receptors, Interleukin-6 / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D017931:DNA Primers; D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1