[Effect of mitochondrial apoptosis on pulmonary fibrosis in rats with severe scald injury].
OBJECTIVE
To explore the role of mitochondrial apoptosis on pulmonary fibrosis in rats with severe scald injury.


METHODS
According to the random digital table, a total number of 32 Wistar rats were divided into 4 groups: sham burn (group A), burn group (group B), 12-week post burn recovery group (group C), and 12-week post burn recovery plus a second burn injury group (group D). In group A and group B, lung tissues were harvested on post burn day 4. After received first burn injury 12 weeks, the group C and group D received separately a second sham burn injury and burn injury. Lung tissues were harvested on post burn day 4 after the second burn injury. All tissues were examined for cells apoptosis by Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL). Pulmonary fibrosis was assessed by Masson trichrome staining and Sirius red staining. The protein expression levels of cleaved Caspase-3, Bax and Bcl-2 were assessed by Western blot.


RESULTS
Both Masson trichrome staining and Sirius red staining showed obvious pulmonary fibrosis in group C and group D. The apoptosis rates of group B, C and D were significantly higher than that in group A ((15.50±3.30)%, (7.88±3.10)%, (15.88±3.23)% vs (2.10±1.07)%, all P<0.05). Compared to group A, cleaved Caspase-3 levels were significantly higher in group B, C and D ((0.59±0.11), (0.33±0.08), (0.73±0.13) vs (0.16±0.05), all P<0.05). The ratio of Bax/Bcl-2 in group B, C and D also increased significantly ((2.08±0.30), (0.83±0.09), (1.54±0.12) vs (0.64±0.05), all P<0.05).


CONCLUSIONS
Severe burn injury can induce pulmonary fibrosis and mitochondrial apoptosis may play an important role in the development of pulmonary fibrosis.
Department of Burns and Plastic Surgery, Burns Institute, the First Hospital Affiliated to the Chinese PLA Hospital, Beijing 100048, China.
X L
XL
Zhang
J K
JK
Chai
B L
BL
Li
L
L
Ma
K N
KN
Yin
D H
DH
Zhang
R
R
Feng
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002056:Burns / Q000378:metabolism* / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D008168:Lung / Q000098:blood supply; D008928:Mitochondria; D011658:Pulmonary Fibrosis / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D044967:Serum / Q000378:metabolism*; D017695:Soft Tissue Injuries
D053148:Caspase 3