Objective

2

To investigate the establishment of post-infectious cough model with lung heat and yin deficiency syndrome in juvenile rats， and to verify the model.

Methods

2

Forty juvenile SD rats were randomly divided into blank group， model group，

Xiebai Zengye Decoction

（泻白增液汤） group and

Juhong Tanke Liquid

（橘红痰咳液） group， with 10 rats in each group. Except for the blank group， rats were exposed to smoke and given lipopolysaccharide nasal drops and capsaicin atomization to prepare post-infectious cough juvenile rat model. The 1st to 18th day was the modeling stage， and the 19th to 26th day of the experiment was the verification stage of the formulas. Since the 19th day， 10 ml/kg of

Xiebai Zengye Decoction

with a concentration of 1.48 g/ml and 5 ml/kg of

Juhong Tanke Liquid

were given by gavage to the corresponding two groups， respectively， while 10 ml/kg of normal saline was administered by gavage to the blank group and model group， once daily for seven days. On the 1st， 10th， and 19th day of the experiment， the rats in the blank group and the model group were compared for changes in anal temperature， paw temperature， precordial temperature， body weight， feces moisture content， and water intake. On the 26th day， the outcomes mentioned above were measured and compared among the four groups. On the 27th day， the cough sensitivity was measured， and the cough latency and the number of coughs within 5 minutes were recorded. The pulmonary function indicators including expiratory time （TE）， enhanced expiratory pause （PENH）， end-expiratory pause （EEP） and relaxation time （RT） were detected， as well as the alveolar lavage fluid cell differential counts and inflammatory factors including tumor necrosis factor α （TNF-α） and interleukin 1β （IL-1β）］ levels. The content of serum cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） were detected， and the value of cAMP/cGMP was calculated. Lung histopathology was observed by HE staining.

Results

2

On the 19th day of the experiment， compared to those in the blank group， the body weight of the rats and the feces moisture content significantly decreased in the model group， while the water intake， anal temperature， paw temperature and precordial temperature increased （

P

＜0.05 or

P

＜0.01）. On the 26th day， the model group had significantly decreased body weight and feces moisture content， increased anal and paw temperatures， increased water intake， shortened cough latency， TE and EEP， growed cough number within 5 minutes， RT and PENH， increased levels of neutrophils， macrophages， lymphocytes， eosinophils in the alveolar lavage fluid， as well as the IL-1β and TNF-αlevels， and serum cAMP level and cAMP/cGMP value than the blank group （

P

＜0.05 or

P

＜0.01）. Compared to those in the model group， the body weight and feces moisture content in the

Xiebai Zengye Decoction

group increased， with decreased anal and paw temperatures， reduced water intake， prolonged cough latency， TE and EEP， decreased RT， PENH and cough number within 5 minutes， reduced levels of neutrophils， macrophages， lymphocytes， eosinophils in the alveolar lavage fluid， as well as the IL-1β and TNF-αlevels， and serum cAMP level and cAMP/cGMP value （

P

＜0.05）； the cough latency， TE and EEP were prolonged in the

Juhong Tanke Liquid

group， with reduced cough number within 5 minutes， decreased neutrophils and lymphocytes， and the level of TNF-α （

P

＜0.05）. HE staining showed that the lung and bronchi tissues of the rats in the blank group were basically normal； the lung tissues of the model group were mostly seen with vascular hyperemia and congestion， inflammatory changes in and around the bronchi， large area of moderately thickened alveolar walls， and widened alveolar spacing； the pathological damage of lung tissues in the

Xiebai Zengye Decoction

group and

Juhong Tanke Liquid

group were alleviated to varying degrees than in the model group， but without significant differences.

Conclusion

2

The post-infectious cough juvenile rat model prepared by combination of smoke exposure， lipopolysaccharide nasal drops and capsaicin atomization has the characteristics of lung heat and yin deficiency syndrome.