To investigate the effect of curcumin on lung injury in rats with acute organophosphorus pesticide poisoning (AOPP) through the cytochrome C/apoptotic protease activating factor-1 (CytC/Apaf-1) pathway.

SD rats were divided into control group, model group, inhibitor group, experimental -L and experimental -H groups, with 10 rats in each group. Except for the control group, the rats in the other 4 groups were administrated with 20 mg·kg^-1 oxomethoate to establish the rat model of organophosphorus pesticide poisoning. After the modeling was successful, the rats in the experimental -L and experimental -H groups were given 100 and 200 mg·kg^-1 curcumin by intragastric administration, and the rats in the inhibitor group were given 67.8 mg·kg^-1 YZ-488 intramuscularily, and the model group and control group were given equal volume of normal saline in the same way by intragastric administration and intramuscularily. Five groups of rats were given the drug once a day for 28 days. Mitochondrial membrane potential detection kits were applied to detect mitochondrial membrane potential (MMP). Enzyme-linked immunosorbent assay method was applied to detect levels of serum interleukin-10 (IL-10); apoptosis in lung tissue was detected by TUNEL; Western blot was applied to detect the expression levels of CytC and Apaf-1 proteins in lung tissue.

The MMP of experimental -L and experimental -H groups, control group, model group, and inhibitor group were (0.64±0.05), (0.78±0.09), (0.93±0.06), (0.51±0.04) and (0.76±0.08) RFU·mg^-1, respectively; IL-10 levels were (67.58±6.82), (104.29±11.37), (148.62±13.54), (32.84±3.51) and (98.74±8.76) pg·mL^-1, respectively; the apoptosis rates were (29.37±3.28)%, (16.58±1.87)%, (5.72±0.64)%, (43.68±4.91)% and (17.32±2.14)%, respectively; the relative expression levels of CytC protein were 0.89±0.07, 0.63±0.05, 0.42±0.04, 1.16±0.12 and 0.65±0.06, respectively; the relative expression levels of Apaf-1 protein were 0.73±0.06, 0.48±0.04, 0.32±0.03, 0.97±0.08 and 0.49±0.05, respectively. The above indexes of the model group were statistically significant compared with those in the experimental -L and experimental -H groups, inhibitor group and control group (all P<0.05).

Curcumin may reduce inflammatory response and oxidative stress in rats by inhibiting the CytC/Apaf-1 pathway, alleviate lung tissue and mitochondrial structural damage, and thereby improve lung injury in rats with AOPP.