The Expression Of FIZZ1in The Smoking-Induced Rat Model Of COPD Lung Tissue And Its Correlation With Airway Inflammation

ObjectiveBronchoalveolar lavage fluid from rats with experimentally induced allergic pulmonaryinflammation contains a novel9.4kDa cysteine-rich secreted protein, FIZZ1(found ininflammatory zone). The objective of this study was to investigate the expression of FIZZ1in thelung tissue from smoking induced COPD rats and thus explored the potential role of FIZZ1inairway remodeling in COPD.MethodsStudy population consisted in70Wistar male rats, adults,3-month-old with medium weight of80g. Biobasis conditions were standard. They were randomly separated into COPD groupand control group average. The70Wistar adult male rats were divided in fourteen lots of5ratseach: the cigarette smoke lot consisting of35Wistar male rats having weight between155and250g was exposed to the smoke twice a day resulted from burning of12cigarettes for3weeks,4weeks,8weeks,12weeks,16weeks,20weeks,24weeks; The control lot, consisting of35Wistarmale rats having weight between150and245g was unexposed to pollutants for3weeks,4weeks,8weeks,12weeks,16weeks,20weeks,24weeks. The exposure was made in one especiallydesigned macrolon cages, essentially according to Escolar and coworkers. These cages(100×80×80cm) equipped with a disposable filter cover having2.5×2.5cm holes that enabled theair to flow out of the cages and thus to be continuously renewed. The smoke was produced bythe burning of a cigarette and was introduced into the chamber with the airflow generated by amechanical ventilator. Blood and tissues were removed. After the cardiopulmonary block wasremoved, we gather BALF of the left lung. Lungs were immediately immersed in10%formalin.Lung tissue was processed by usual histopathological technique:10%formalin-fixed, thepulmonary tissue preparation made for morphometric study considered the pulmonary anisotropy.Assessment of the areas, the structures thickness in the pulmonary tissue and cell number inBALF were made on serial isotropic randomly sections. Serial, classical stained (HE, van Gieson, Orcein, reticulin fibers) and immunohistochemical (SMA) sections were used to detect the IL-4,TNF-α in both BALF and serum. Detect the FIZZ1in the lung tissue. Lungs were cut inlongitudinally axe and so each section contains hilum, mediopulmonar respectively peripheralpulmonary area having the alveolar and aerial ducts distribution compatible with the system ofstructures counting on randomized sections.Results(1) HE staining showed that there was no significant pathological change in lung tissue in controlrats. The pathological change in COPD group happened on3weeks cigarette smoke,significantly on12weeks,16weeks. We found out the presence of bronchiolo-alveolarattachment destruction in cigarette smoke group, less frequent in control group. When comparedwith rats in control group, the lung tissue from asthmatic group showed the airway wallthickening, lumina narrowing, epithelial detachment, increased airway smooth muscle mass,inflammatory cell infiltration. In control group, inflammatory reactions were not observed.COPD rat model was made successfully on20weeks later.(2) Inflammatory cells in BALF：Total number of inflammatory cells in BALF in the cigarettesmoke rats group was significantly higher at each time point (P<0.01)，increased significantlywith the explore time. There was no significant difference in lymphocytes between cigarettesmoke group and control group.(3) Elisa ananlysis of the IL-4, TNF-α in BALF and serum：The expression of TNF-α in theserum of cigarette smoke group was no significant difference until24weeks between two groups.The expression of TNF-α in BALF was gradually increased with the intensification of COPDinflammation, and continuous maintain the peak concentration in16,20and24weeks (P<0.05).IL-4in the serum was no significant difference between the two groups (P＞0.05)；IL-4in BALFof model rats increased slightly at16,20and24weeks, the difference was statistically significant(P＜0.05).(4)Positive FIZZ1staining was highly expressed in peribronchail lung sections isolated from thecigarette smoke group compared with the control group. The expression of FIZZ1was graduallyincreased, and reached the peak concentration at the20weeks by the western blot analysis. (5) The FIZZ1expression had positive correlation with the expression of inflammatory cells,IL-4、TNF-a in the BALF and TNF-a in the serum, but had no correlation with the IL-4expression in the serum.Conclusions(1) We had established a rat COPD model based on natural cigarette smoke exposure, usable fora further approach in human non-smoker COPD investigation.(2) FIZZ1mainly located at bronchial epithelial cells, alveolar epithelial cells, pulmonaryvascular endothelial cells, alveolar macrophages, bronchial smooth musclelayer and fibrosis ofthe lung interstitium.(3) FIZZ1perhaps could promote neutrophils, macrophages and lymphocytes gathering in theairways, and promote the synthesis and secretion of IL-4, TNF-α and other inflammatorymediators. It was suggested that FIZZ1may be involved in the occurrence and development ofCOPD.