[Effects of vitamin A on the proliferation and apoptosis of alveolar cells of experimental emphysema in rats].
OBJECTIVE
To study the effect of vitamin A on experimental emphysema in rats, and on the proliferation and apoptosis of the alveolar cells.


METHODS
Twenty-four Wistar rats were randomly divided into 3 groups: a control group (C), an emphysema model group (M) and a vitamin A treatment emphysema group (V), with 8 rats in each group. Experimental emphysema was induced by instilling elastase into the lungs of the rats in group M and group V. Vitamin A injection via esophagus was given from the 5th week to the 8th week after elastase instillation. At the end of 8th week, the lungs of the rats were extracted and fixed. The pathological sections were observed by HE staining. The proliferating cell nuclear antigen (PCNA) was examined by immunohistochemical method. The apoptosis of the alveolar cells was observed by the method of terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL).


RESULTS
The mean alveolar number (MAN) in the rats of group M (43 +/- 11) was significantly lower than those in the rats of group C (101 +/- 15) and group V (56 +/- 8). The mean alveolar area (MAA) in the rats of group M [(3763 +/- 504) microm2] was significantly higher than those in the rats of group C [(1919 +/- 270) microm2] and group V [(2710 +/- 276) microm2]. The proliferation index (PI) in the rats of group M [(30.7 +/- 7.6)%] was significantly higher than that in the rats of group C [(9.9 +/- 1.8)%] but was significantly lower than that in the rats of group V [(17.3 +/- 3.5)%]. The apoptosis index (AI) in the rats of group M [(22.0 +/- 4.6)%] was significantly higher than those in the rats of group C [(9.8 +/- 1.7)%] and group V [(17.3 +/- 3.5)%]. PI/AI in the rats of group M (1.03 +/- 0.19) showed no difference compared to that in the rats of group C (1.45 +/- 0.52), but was lower than that in the rats of group V (2.73 +/- 0.64).


CONCLUSIONS
Vitamin A was demonstrated to promote the proliferation of the alveolar cells and inhibit their apoptosis in experimental emphysema of rats, and hence contribute to the improvement of emphysema.
Hou
Gang
G
Institute of Respiratory Disease, China Medical University, Shenyang 110001, China.
Wang
Qiu-Yue
QY
Wang
Xiao-Qiu
XQ
Kang
Jian
J
Yu
Run-Jiang
RJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D004195:Disease Models, Animal; D008297:Male; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000187:drug effects*; D011656:Pulmonary Emphysema / Q000188:drug therapy / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D014801:Vitamin A / Q000494:pharmacology* / Q000627:therapeutic use
D014801:Vitamin A