Expression of the pulmonary surfactant in rat with paraquat-induced acute lung injury

Abstract

To explore the expression of pulmonary surfactant in rats with paraquat-induced acute lung injury. A total of 36 SD rats were randomly divided into the control group (n=6) and paraquat group at 6, 12, 24, 48, 72 h five time points, each time points 6 rats. All of the rats were injected with paraquat (80 mg/kg) for once. The specimens were collected at 0 h (instant) after paraquat intoxication in the control group, and at the corresponding point in time in the paraquat each time point groups. The pathology changes of lung tissue were observed by HE staining, thiobarbituric acid method was used to detect malondialdehyde (MDA) level, and Western blot method was used to analyze the relative expression of surfactant protein (SP)-A and SP-D in bronchoalveolar lavage fluid (BALF) with time. As compared to control, the levels of MDA in BALF were significantly higher at 6, 24, 48 h after paraquat intoxication ((4.19 ± 0.12), (3.33 ± 0.08), (3.52 ± 0.08) vs (2.82 ± 0.15) nmol/mg, all P<0.01), no significantly different at 12, 72 h ((2.76 ± 0.13), (2.79 ± 0.10) nmol/mg, both P>0.05); the relative expression of SP-A in BALF were significantly higher at 6 h after paraquat intoxication (1.32 ± 0.19 vs 1.00 ± 0.19, P<0.01), lower at 24, 48 h (0.43 ± 0.07, 0.67 ± 0.08, both P<0.01), and no significantly different at 12, 72 h (0.98 ± 0.15, 0.79 ± 0.18, both P>0.05); the relative expression of SP-D in BALF were significantly higher at 6, 12 h after paraquat intoxication (1.54 ± 0.33, 1.64 ± 0.37 vs 1.00 ± 0.23, both P<0.01), no significantly different at 24, 48 h (1.07 ± 0.19, 0.97 ± 0.15, both P>0.05), and reached the peak at 72 h (2.15 ± 0.26, P<0.01); the expression of MDA, SP-A and SP-D were characterized by the state of fluctuation with increased first, reduced after, and finally increased. The expression of SP-A, SP-D increase at the early stage of the paraquat-induced acute lung injury in rat, which can reflect the degree of lung injury.