Effect of hyperoxia on Notch receptor in alveolar epithelial type Ⅱ cells of preterm rats / 中华急诊医学杂志

ABSTRACT

Objective To observe the effects of hyperoxia on Notch 1 receptor of alveolar epithelial type Ⅱ cells (AEC Ⅱ), in a hetcrocellular culture of alveolar epithelial type Ⅱ cells and lung flbroblasts(LF), in order to explore Notch signaling in hyperoxic induced lung injury and thus make theoretical basis for prevention and treatment of a acute/chronie neonatal lung injury. Method Twelve Spragne Dawkey female rats with 200～220 g and 3 Spragne Dawkey male rats with 220～250 g were offered from experimental animal centre of Tongji Medical Colleege, Huazhong University of Science and Technology. The AEC Ⅱ/ LF co-culture system was established successfully. AEC H s from premature rats were randomly assigned to 2 groups air control group and hyperoxia group. Air control group was kept in room air 50% ml/L CO2 enviromnent at 37°C, while hyperoxia group was exposed to 950 ml/L O2 + 250 ml/L CO2. Immuno-histochemistry was taken to detect Notch 1. Fluorescent quantitafive PCR was used to quantify the Notch 1 mRNA. MTT method was taken to assess cen proliferation viability.Flow eytometry double label method was used to detect cell percentages. Results In hyperoxia groupNotch 1 activation was inhibited, and Notch 1 mRNA decreased to 0.43,0.29,0.11,0.03 fold of control (95% confidence limit). AEC Ⅱ percentage descended predominantly[ 24 h hyperoxia group vs. control group (68.92±6.88)%vs. (90.35±4.01)%, P =0.006;48 h hyperoxia group vs. control group (38.03±3.27) vs. (61.47±4.81)%, P =0.000;72 h hyperoxia group vs. control group(20.13±4.45)% vs. (52.05±3.35)%, P =0.000;96 h hyperoxia group vs. control group(8.17±1.99)% vs. (52.59±2.93)%, P =0.0001 while that d AECI rised[24 h hyperoxia group vs. contrd group(0.11±0.03)% vs. (0.01±0.01)%, P=0.006;48h hyperoxia group vs. control gnmp(49.73±3.45)% vs. (16.13±2.13)%, P =0.000;72 h hyperoxia group vs. control group (52.43±3.14) % vs. (5.98±0.95) %, P = 0.000;96h hyperorxia group vs. control group(19.85±3.26)% vs. (29.03±3.16)%, P =0.007]. Comclusions Hyperoxia may inhibit Notch signaling pathway, which can weaken proliferation and disdifferentiation of AEC Ⅱ s. Investigations on how to control Notch signaling will provide fresh thoughts for alveolar epithelium repairing.