To investigate the effect and significance of insulin-like growth factor-binding protein related protein 1(IGFBPrP1)on lung tissue in SD rats and beagles.

①Sixty healthy male SD rats were randomly divided into A group(n=10)、B group(n=25)and C group(n=25), and were respectively injected with the same doses of saline, Ad-EGFP and Ad-IGFBPrP1 via the caudal vein.Lung tissues were obtained for analysis at week 1, 2, 4, 6 and 9.②Eighteen healthy male beagles were randomly assigned to three groups of 6 each.Beagles in D group had a free access to food and water.Beagles in E group were given subcutaneous injection of thioacetamide(TAA)(12 mg/kg, twice per week). Beagles in F group were given subcutaneous injection of TAA(12 mg/kg, twice per week), and IGFBPrP1-Ab(5 μg/kg, once per week)were injected into portal vein from week 5.Lung tissues of all beagles were obtained for analysis at week 12.The same methods of group C and E could cause hepatic fibrosis to SD rats and beagles successfully.HE staining and Siris Red staining were observed to investigate the pathomorphological changes and deposition of collagen fibers in lung of SD rats and beagles.The expressions of IGFBPrP1, transforming growth factorβ1(TGFβ1), fibronectin(FN)and interleukin1(IL-1β)of lung tissues in SD rats and IGFBPrP1 in beagles were detected by immunohistochemical staining.

①SD rats: Comparing with A and B group, there appeared inflammatory injury after the transfection of Ad-IGFBPrP1 and the degree of inflammation was gradually advanced with time, and lung fibrosis and increase of collagen fibers were observed at 9 weeks in C group.The expression of IGFBPrP1 protein in C group increased and peaked(1.5±0.03)at 2 weeks after transfection, then gradually decreased.The level of IL-1βup-regulated and peaked(1.94±0.03)at 4 weeks after transfection and later gradually down-regulated.The level of TGFβ1 increased from 1 week, and peaked(2.38±0.01)at 9 weeks.The expression pattern of FN was similar to TGFβ1, and it peaked at 9 week s(1.23±0.05). ②Beagles: Comparing with D group, E group showed pathomorphological changes and deposition of collagen fibers.Comparing with E group, the degree of pathomorphological changes and the content of collagen fiber decreased in F group.The expression of IGFBPrP1 protein in E group(1.39±0.20)and F group(1.05±0.16)increased comparing with D group(0.50±0.14), and that in F group was less than E group(P<0.01).

IGFBPrP1 contributes to the inflammatory injury and fibrosis of the lung tissue in SD rats, and it can also cause varying degrees of damages to the lung tissue in beagles, which may not be a tissue-specific pathogenic factor.