Objective:To investigate the protective effect of racanisodamine on lung injury in mice exposed to irradiation.Methods:C57BL/6 mice were randomly divided into control group, racanisodamine group, 18 Gy irradiation group (model group) and racanisodamine combined with 18 Gy irradiation group (treatment group), with 5 mice in each group. The mice in the treatment group received racanisodamine (5 mg/kg) intraperitoneally 3 d before irradiation and contained the whole experiments. Then, single chest irradiation of 18 Gy X-rays was performed both in the model and treatment groups. The racanisodamine group and treatment group received racanisodamine intraperitoneally once a day until 6 weeks after irradiation. The mice were killed at 6 weeks after irradiation. The lung histopathology was observed by HE staining. Serum and bronchial alveolar lavage fluid (BALF) inflammatory cytokines such as TNF-α, IL-1β and IL-6 were determined by ELISA method. Cell senescence was detected by SA-β-Gal staining. The expressions of Nrf2, p-Nrf2 and p62 in lung tissue were performed by immunehistochemistry and Western blot assays.Results:Compared with the model group, the scores of HE staining were decreased ( t=8.66, P<0.01), the number of infiltrated inflammatory cells in BALF were decreased ( t=10.70, P<0.01), and protein concentration in BALF had lower levels ( t=6.75, P<0.01), the serum TNF-α, IL-1β and IL-6 were decreased significantly ( t=8.17, 4.58, 6.54, P<0.01), the activity of SA-β-gal was decreased, and the expressions of Nrf2, p-Nrf2 were enhanced ( t=6.42, 7.30, P<0.01), while the expression of p62 was reduced ( t=4.62, P<0.01) in the treatment group. Conclusions:Racanisodamine plays the protective effect of radiation-induced lung injury by alleviating inflammation associating with the activating of Nrf2-related pathway, which reversed radiation-induced cell senescence.

Background With the change of the national energy development layout, Qingyang has seen a situation where oil exploitation and agriculture go hand in hand, which may lead to local soil pollution if not taken seriously. Objective To evaluate the distribution characteristics, possible sources, and ecological risks of heavy metals in farmland soils around the main production areas of Changqing Oilfield. Methods A total of 60 farmland soil samples were collected from Zhengning County, Zhenyuan County, and Qingcheng County of Qingyang City, and the contents of heavy metals such lead (Pb), mercury (Hg), chromium (Cr), cadmium (Cd), and arsenic (As) in farmland soil were detected according to GB 15618-2018 Soil environmental quality—Risk control standard for soil contamination of agricultural land (on trial). The soil background value of Gansu Province was used as the denominator in the calculation of pollution index, and the pollution characteristics and ecological characteristics of selected five heavy metals in farmland soil were evaluated by single-factor pollution index (P_i), Nemerow comprehensive pollution index (P_N), and potential ecological risk index. Results The levels of Pb, As, and Hg in farmland soils around Changqing Oilfield, the levels of Cr and Cd in Qingcheng County, and the level of Cd in Zhengning County were higher than the corresponding soil background values of Gansu Province, but lower than the national soil environmental quality standard. The single-factor pollution indexes (P_i) were: Hg, 2.14; Pb, 1.24; As, 1.13; Cr, 0.78; Cd, 0.67, which indicated that Hg were graded as moderate pollution, Pb and As were slight pollution, and Cd and Cr were not polluted. The Nemerow comprehensive pollution indexes (P_N) were: Cr, 0.92; Cd, 1.08; As, 1.20; Pb, 1.68; Hg, 3.85, which indicated that Cr was graded as no pollution, Cd, Pb and As were mild pollution, and Hg was severe pollution. The variation coefficients of Hg and Cd in Zhenyuan County and that of Hg in Qingcheng County were 60.00%, 50.00%, and 50.00%, respectively, which were all greater than 50%, indicating that the pollution of above heavy metals in the location was subject to human activities. The potential ecological risk indexes (E_r) of Pb, Cr, Cd, As, and Hg were 6.20, 1.55, 20.05, 11.28, and 81.64, respectively, indicating that Hg was graded as strong ecological risk, and the other four heavy metals were mild ecological risk. The comprehensive potential ecological risk index (R_RI) was 124.48. Combined with the potential ecological risk index of Hg, the comprehensive potential ecological risk of the five heavy metals in local farmland soils was considered to be at a strong ecological risk level. Conclusion Although the average values of selected five heavy metals in farmland soils surrounding the main production areas of Changqing Oilfield are qualified with the national soil environmental quality standards, they exceed corresponding soil background values of Gansu Province, and there are signs of human influence and potential ecological risks of different degrees.