[Effect of oxidative stress-associated damage to the lung tissue caused by different body mass index in the rat models].

Objective: To investigate the influence of different diets on serum protein expression levels of 4-hydroxynonenal (4-HNE), thioredoxin (Trx), thioredoxin reductase (TrxR) and the activities of Trx and TrxR, and to explore the effect of damage to the lung tissue and the underlying mechanisms of different body mass index caused by different diets in the rat models . Method: Healthy clean male SD rats were randomly divided into normal group, emaciation group and fat group, which were raised by different diets for 6 months.Then the rats were sacrificed and the serum and lung tissue were prepared. The levels of 4-HNE, Trx and TrxR in peripheral blood were quantitatively analyzed by enzyme-linked immunosorbent assay(ELISA), and the activities of Trx and TrxR were measured by chemical methods. Results: Compared with the normal group, the lung tissue had more apparent emphysema in the emaciation and the fat groups under light microscope, and more inflammatory cell infiltration in alveolar septum was observed in the fat group.The levels of 4-HNE in the fat group[(24.7±8.7)mg/L]was significantly higher than that in the normal group[(15.4±4.7)mg/L, P<0.05)], but there was no significant difference(P>0.05)in the levels of 4-HNE between the emaciation and the normal groups. The levels of TrxR in the emaciation group[(7.7±1.4)μg/ml]was significantly higher than that in the normal and the fat groups[(6.2±1.1), (4.9±1.4)μg/ml, all P<0.05)]. The level of TrxR in the fat group was significantly lower than that in the normal group(P<0.05); The differences in the levels of Trx among the 3 groups were not significant(P>0.05). The activity of Trx in the emaciation group[(32.4±8.5)×10(-3)A·min(-1)·mg(-1)]was significantly higher than that in the normal group[(19.6±3.3)×10(-3)A·min(-1)·mg(-1)]and the fat group[(11.3±7.5)×10(-3)A·min(-1)·mg(-1), all P<0.01]. The activity of Trx in the fat group was significantly lower than that in the normal group(P<0.05). The activity of TrxR in the emaciation group[(17.6±4.6)×10(-3)A·min(-1)·mg(-1)]was significantly higher than that in the fat group[(7.8±2.3)×10(-3)A·min(-1)·mg(-1), P<0.01], but the TrxR activity of the 2 groups showed no significant difference as compared with the normal group(P>0.05). Conclusion: Both high BMI and low BMI can affect the oxidative stress of the body, resulting in increased oxidants and decreased antioxidants, and can cause damage to the lung tissue in the rat models.