RESUMO
Objective Pulmonary function testing is a commonly used indicator for clinical evaluation of the degree of pulmonary fibrosis in patients. This paper aims to investigate the dynamic changes of lung function in mice with pulmonary fibrosis and to establish a range of reference values for lung function parameters in normal Kunming mice. Methods Twenty-eight SPF Kunming mice were randomly divided into normal control group (n=14) and model group (n=14). After anesthesia with 10% chloral hydrate, the normal control group only underwent tracheal puncture. The model group received intratracheal puncture and injection of bleomycin (BLM) (5 mg/kg body weight), and the lung function indicators of all mice were detected in the same order on the 1st, 2nd, 3rd and 4th weekends after modeling: Ti, Te, PIF, PEF, TV, EV, RT, MV, f, Penh and EF50. Results After intratracheal BLM injection, mice in the model group showed decreased hair softness and smoothness, hair loss and decreased activity after the 2nd week. Compared with the control group, Ti, Te and RT values in the model group significantly increased at week 4 (P<0.05), while the values of PEF, RT, MV, f and EF50 decreased significantly at the same week (P<0.05). Compared with the model group at week 1, the differences in Ti, Te, RT and f values at week 2, 3 and 4 were statistically significant (P<0.05); the differences in MV and EF50 values at week 3 and 4 were statistically significant (P<0.05); while the PIF values only showed differences at week 4 (P<0.001). Compared with the Penh values in the control group at week 2, 3 and 4 (0.553±0.189, 0.662±0.164, 0.712±0.189), the differences of the model group (0.820±0.205, 0.936±0.188, 1.053±0.236) showed statistical significance (P<0.001). Compared with the model group at week 1, the differences of Penh values in the model group only showed statistical significance at week 3 and 4 (P<0.05). Through four-week lung function test, various parameters were obtained, among which the normal range of the main index Penh value was 0.27-0.88. Conclusion The lung function detected by the non-invasive whole body plethysmography system was stable and reliable with good effects; the lung function in mice with the BLM-induced pulmonary fibrosis continued to decrease within four weeks. Penh, which reflects airway resistance, can be used for overall screening of the lung function among the test mice after two weeks of modeling.
RESUMO
BACKGROUND: Low spirometric forced vital capacity(FVC) in conjunction with a normal or high ratio of the forced expiratory volume at 1 second to the forced vital capacity(FEV1/FVC%) has traditionally been classified as a restrictive abnormality. However, the gold-standard diagnosis of a restrictive pulmonary impairment requires a measurement of the total lung capacity (TLC). This study was performed to determine the predictive value of spirometric measurements of the FVC for diagnosing a restrictivepulmonary abnormality. METHODS: Test results from 1,371 adult patients who undertook both spirometry and lung volume measurements on the same visit from January 1999 to December 2000 were enrolled in this study. The test values for the FVC, the TLC that was below 80% of predicted value, and a FEV1/FVC% that was below 70%, were classified as being abnormal. RESULTS: Of the 1,371 patients, 353 patients had a reduced a FVC. Of these patients, 186 patients had a reduced TLC. Therefore, the positive predictive value was 52.7%. Of the 196 patients with a normal FEV1/FVC% and a reduced FVC, 148(75.5%) patients had a lower TLC. Thirty eight (24.2%) patients out of 157 patients with a low FEV1/FVC% and a low FVC showed a restrictive defect. CONCLUSION: Spirometry is useful to rule out a restrictive pulmonary abnormality, but a restrictive pattern on the spirometry dose not mean there is a true restrictive disease. For the patients with a low FVC, TLC measurements are essential for diagnosing a restrictive pulmonary impairment.