[A study on the model of tuberculous pleurisy and intrapleural inflammatory and immunological responses in rats].
OBJECTIVE
To develop a rat model of tuberculous pleurisy and to explore the mechanism of intrapleural inflammatory and immunological responses.


METHODS
Fifty Wistar rats were injected intrapleurally with 0.03 mg of standard human mycobacterium tuberculous bacilli H37Rv each. The rats were killed in group on days 1, 2, 3, 5, 7, 10, 15, 20, 30 and 60 after the day of intrapleural injection. The thorax was opened and the amount of pleural effusion was recorded, and histopathology of pleural tissues and lung tissues were observed. The white blood cell (WBC) count and differentials, levels of total protein (TP), glucose (GLU) and lactic dehydrogenase (LDH) of pleural effusions were determined. Pleural fluid was analyzed for the levels of soluble intercellular adhesion molecule-1 (sICAM-1), transforming growth factor beta1 (TGF-beta1) and interferon gamma (IFN-gamma) by using appropriate bioassays. Ten rats were intrapleurally received 2 ml of normal saline and another 10 rats received 2 ml of undiluted PPD solution each as control.


RESULTS
Bilateral pleural effusions appeared within 15 days in all rats intrapleurally received tuberculous bacilli. The peak amount of pleural fluid was on day 5 (6.7 +/- 0.5 ml). The neutrophils were the predominant cells for the first 24 hours, and then were followed by lymphocytes. In the pleural fluid, total protein concentration was between 51-55 g/L. The levels of glucose and LDH were 5.2 mmol/L and 18.1 micromol.s(-1).L(-1) on day 1 and changed to 2.8 mmol/L and 28.9 micromol.s(-1).L(-1) on day 15 respectively. The biochemistry parameters were in accordance with characteristics of tuberculous pleurisy. The sICAM-1 level increased early (21.9 ng/ml on day 1) and peaked on day 3 (38.0 ng/ml), then decreased over time (4.4 ng/ml on day 15). The level of IFN-gamma was 41.2 pg/ml on day 1 and increased and maintained at high levels over time. TGF-beta1 levels increased and peaked on day 7 (47.2 ng/ml), and then on day 15 decreased to a level lower than that of day 1. The ratio of IFN-gamma/TGF-beta1 increased from 1.32 on day 1 to 5.69 on day 15. Correlation analysis showed that sICAM-1 and IFN-gamma were closely related with WBC count and its differentials, as well as with LDH levels. Histopathological study revealed early pleural inflammation and late caseation.


CONCLUSIONS
Wistar rats can be used as an experimental model for tuberculous pleurisy. Tuberculous inflammatory and immunological responses in acute tuberculous pleurisy is enhanced rather than suppressed.
He
Qiao
Q
Department of Pathology, Guangzhou Chest Hospital, Guangzhou 510095, China.
Xie
Can-Mao
CM
Tan
Shou-Yong
SY
Zhang
Ke-Xun
KX
Deng
Xiao-Hua
XH
Zhu
Peng-Bo
PB
Yi
Xiao-Ping
XP
Zhang
Yuan-Liang
YL
Cai
Xing-Shan
XS
Huang
Li-Jing
LJ
Liu
Yan
Y
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis*; D007371:Interferon-gamma / Q000096:biosynthesis; D007958:Leukocyte Count; D018655:Lymphocyte Count; D009169:Mycobacterium tuberculosis; D010994:Pleura / Q000378:metabolism* / Q000473:pathology; D010996:Pleural Effusion / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D014396:Tuberculosis, Pleural / Q000209:etiology / Q000276:immunology* / Q000378:metabolism*
D016212:Transforming Growth Factor beta; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma