Objective:To investigate the effects of different doses of oxiracetam (ORC) on the neurological impairment and oxidative stress ability of lead(Pb)-exposed rats.Methods:Total 32 male SD rats with SPF grade were randomly divided into control group, the lead-exposed group, low-dose ORC intervention group and high-dose ORC intervention group according to the random number table method, with 8 rats in each group.The neurobehavioral indexes of rats were measured by gait score, tail flicking test, hindlimb support test and Morris water maze test.The lead content in hippocampal tissue was detected by spectrophotometry.The cell morphology of hippocampal tissue was observed by HE staining.Superoxide dismutase (superoxide dismutase, SOD) level in hippocampal tissues was detected by xanthine oxidase, and the level of malondialdehyde (MDA) in the hippocampus tissue was detected by the thiobarbiturate, and the level of glutathione peroxidase (GPx) in the hippocampus tissue was detected by chemical colorimetric.SPSS 24.0 software was used for statistical analysis, one-way ANOVA was used for multiple group comparisons and LSD- t test was used for further pairwise comparisons. Results:(1)After 8 weeks of lead exposure, there was no significant difference in body weight among the 4 groups( F=0.869, P=0.469). (2)Results of neurobehavioral indicators: there were statistically significant differences in gait scores, tail flick time, hind limb deployment distance, escape latency, and number of crossing platforms among the four groups of rats ( F=7.854, 13.630, 8.484, 23.485, 45.457, all P<0.05). The gait score, tail flick time, hind limb deployment distance, and escape latency of the lead-exposed group rats were higher than those of the control group (all P<0.05), while the number of crossing platforms was lower than that of the control group ( P<0.05). The gait score, tail flick time, hind limb deployment distance, and escape latency of the high-dose ORC intervention group were lower than those of the lead exposed group (all P<0.05), and the number of crossing platforms was higher than that of the lead exposed group ( P<0.05). (3)Lead content in hippocampal tissue: there was a statistically significant difference in lead content in the hippocampus of the four groups( F=309.013, P<0.001). The lead contents of lead exposed group ((1.21±0.10)μg/g), low-dose ORC intervention group ((1.03±0.10)μg/g) and high-dose ORC intervention group ((1.02±0.06)μg/g) were higher than that of the control group((0.02±0.00) μg/g) (all P<0.05), while the lead content in the low-dose ORC intervention group and high-dose ORC intervention group were both lower than that of the lead exposed group (both P<0.05). (4) HE staining showed that compared with the control group, the hippocampal tissue cells in the lead exposed group were arranged disordered, the tissue was loose, and the number of cells was reduced.Compared with the lead exposed group, the hippocampal histiocytes were closely arranged and regular, and the nuclei were fuller.(5)Oxidative stress levels in hippocampal tissue: there were significant differences in MDA, GPx content and SOD activity of hippocampal tissues in the four groups( F=69.879, 56.757, 11.644, all P<0.001). The levels of SOD ((2.03±0.18)U/mg, (3.42±0.26)U/mg), GPx((67.29±7.94)nmol/mg, (89.50±7.94)nmol/mg) in the hippocampus tissue of the lead exposed group were lower than those of the control group (all P<0.05), while the content of MDA was higher than that of the control group((43.73±3.74) nmol/mg, (16.42±1.60) nmol/mg)( P<0.05). The levels of SOD ((3.32±0.12) U/mg) and GPx ((84.11±6.26) nmol/mg) in the high-dose ORC intervention group were higher than those in the lead exposed group (both P<0.05), while the levels of MDA ((21.05±2.56) nmol/mg) was lower than that in the lead exposed group ( P<0.05). Conclusion:ORC can alleviate neurological damage in rats caused by lead exposure, which may be related to the up-regulation of antioxidant capacity of hippocampal tissues, thereby improving pathological damage.