As the main active compound of Stephania tetrandra S. Moore, tetrandrine (TET) has been used to treat silicosis for nearly 50 years. TET has clear therapeutic effect on pulmonary fibrosis and lung cancer. A recent study suggests that TET may inhibit the replication of SARS-CoV-2 by blocking the two-pore channel 2 (TPC2), revealing its potential as a natural medicine to treat COVID-19. To explore the material basis of TET targeting lung efficacy and its potential toxicity, available literatures related to the pharmacological activity on pulmonary, dosage, toxicity and pharmacokinetics of TET are systemically reviewed. The prospect and current problems of TET to be a therapeutic agent for COVID-19 are further investigated on this basis.

Objective:To improve the primary culture method of rat pulmonary microvascular endothelial cells(PMVECs) and obtain purified PMVECs.Methods:The modified tissue block pasted culture method was used to isolate and culture Wistar rat PMVECs. The morphous of cultured cells were observed by microscopy. The cultured cells were identified by detecting factor Ⅷ related antigen and binding isolectin B4. Results and Conclusion:The morphous of cultured primary PMVECs in vitro showed short fusiform shape or polygon, and the monolayer of cultured cells displayed the shape of pavingstone. But the morphous changed followed the transfer of culture and the change of culture condition. The cultured cells had characterization of binding isolectin B4 and negative immunocytochemical staining for factor Ⅷ related antigen. The cultured PMVECs have good growth state and purity,and can be subcultringed stably.The observation of cell morphous integrating with immunocytochemical staining is a reasonable identification method for PMVECs.

Objective To establish a method of isolation, purification, primary culture and identification of alveolar type Ⅱ epithelial cells(AT-Ⅱ).Methods The AT-Ⅱs were isolated from Wistar rats by trypsin,purified by differential centrifugation, erythrocyte spallation, differential adherence and immune adherence, and identified by observing the morphology of cultured cells under the inverted phase and tannic acid staining. Results and Conclusion The cultured primary AT-Ⅱs in vitro presented single or island form growth, and their shapes were round or elliptical. A great deal of fine particles showed sharp contrast, and were observed in intracytoplasm. The cell nuclei were clear. They were positive for tannic acid staining.The primary culture AT-Ⅱs obtained from improved isolation and purification have good growth state and purity, and are suitable for research in vitro.

OBJECTIVETo establish of acute respiratory distress syndrome (ARDS) model in canine after inhalation of perfluoroisobutylene (PFIB), and to observe the progressing of lung injury, and to study the mechanisms of injury.

METHODSA device of inhalation of PFIB for canine was made. The concentration of PFIB was 0.30 - 0.32 mg/L. Serum IL-6 and IL-8 were dynamically measured. Clinical manifestations, pathology of organs in canine were observed.

RESULTS(1) During inhalation, the concentration of PFIB remained stable; (2) After inhalation, blood arterial oxygen partial pressure fell gradually, and eventually met the criteria for diagnosing ARDS; (3) The level of IL-8 in serum rises significantly after inhalation (P < 0.05), whereas that of IL-6 was not obviously altered (P > 0.05); (4) Within 6 hours after inhalation, no abnormality in canine was observed, but afterwards symptoms gradually appeared, and typical breath of ARDS, such as high frequency and lower level could be seen in later phase; (5) Pathological examination showed severe congestion, edema and atelectasis in most part of both lungs, and signs of anoxia in other organs.

CONCLUSIONS(1) The device designed is capable of ensuring control of inhalation of PFIB; (2) Exposure to PFIB for 30 mins, canines all met the criteria for diagnosing ARDS 22 hours after inhalation, therefore the modeling is successful; (3) PFIB specifically damages the lung by causing excessive inflammation.

Administration, Inhalation ; Animals ; Disease Models, Animal ; Dogs ; Female ; Fluorocarbons ; toxicity ; Interleukin-6 ; blood ; Interleukin-8 ; blood ; Lung ; drug effects ; pathology ; Male ; Random Allocation ; Respiratory Distress Syndrome, Adult ; blood ; chemically induced

Acute lung injury(ALI) is an acute hypoxic respiratory insufficiency syndrome. It tends to develop into acute respiratory distress syndrome(ARDS). Renin angiotensin system(RAS) has been proved to be closely related to the development of ALI/ARDS. The classic axis of RAS, angiotensin converting enzyme(ACE)-angiotensin(Ang) Ⅱ-Ang Ⅱtype 1 receptor(AT1R) axis, induces ALI/ARDS by inducing excessive inflammatory response, damaging alveolar barrier function, triggering coagulation dysfunction and other mechanisms. ACE2-Ang(1-7)-MAS axis of RAS can antagonize ACE-Ang Ⅱ-AT1R axis, and improve ALI/ARDS by inhibiting inflammatory response, antagonizing oxidative stress and reducing pulmonary vascular permeability. ACE inhibitors, drugs to reduce the level of Ang Ⅱ, AT1R blockers, AT2R stimulants, recombinant ACE2,mesenchymal stem cells with ACE2 overexpression, Ang1-7 and lipoxin A4 have been proved to improve ALI/ARDS in animal experiments. These results provide a new target for prevention and treatment of ALI/ARDS and improvement of prognosis.