What increases type III procollagen mRNA levels in lung tissue: stress induced by changes in force or amplitude?
We hypothesized that stress determined by force could induce higher type III procollagen (PCIII) mRNA expression than the stress determined by amplitude. To that end, rat lung tissue strips were oscillated for 1h under different amplitudes [1, 5 and 10% of resting length (L(B)), at 0.5 x 10(-2) N] and forces (0.25 x 10(-2), 0.5 x 10(-2) and 10(-2)N, at 5% L(B)). Resistance (R), elastance (E) and hysteresivity (eta) were analysed during sinusoidal oscillations at 1Hz. After 1h of oscillation, PCIII mRNA expression was determined by Northern-blot and semiquantitative RT-PCR. Control value of PCIII mRNA was obtained from unstressed strips. E and R increased with augmenting force and decreased with increasing amplitude, while eta remained unaltered. PCIII mRNA expression increased significantly after 1h of oscillation at 10(-2)N and 5% L(B) and remained unchanged for 6h. In conclusion, the stress induced by force but not by amplitude led to the increment in PCIII mRNA expression.
Garcia
Cristiane S N B
CS
Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Ilha do Fundão, 21949-900 Rio de Janeiro, RJ, Brazil.
Rocco
Patricia R M
PR
Facchinetti
Lívia D
LD
Lassance
Roberta M
RM
Caruso
Pedro
P
Deheinzelin
Daniel
D
Morales
Marcelo M
MM
Romero
Pablo V
PV
Faffe
Débora S
DS
Zin
Walter A
WA
D000818:Animals; D001696:Biomechanical Phenomena; D024061:Collagen Type III / Q000235:genetics* / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical
D024061:Collagen Type III; D012333:RNA, Messenger