To investigate the effect of autophagy-related protein 12 (ATG12) on apoptosis and autophagy in mice with hypoxic-ischemic encephalopathy (HIE) and its molecular mechanism.

The ATG12 low expression mouse model was constructed by injecting adeno-?associated virus (AAV) into the tail vein. Forty mice were divided into a sham operation group, HIE model group, negative control virus HIE model (NC-HIE) group and ATG low expression virus HIE model (ATG12 shRNA-HIE) group. The mice in the HIE model group were treated with hypoxia (8﹪ oxygen + 92﹪ nitrogen) for 2.5?h after ligation of the left carotid artery. The mice in the sham operation group were not treated with ligation and hypoxia. After hypoxia and hypoxia treatment, the expression level of ATG12 mRNA in the brain tissues was detected by real-time PCR. The levels of SOD and MDA in the brain tissues of each group were detected. The apoptosis level of the brain tissues was detected by Tunel method. The expressions of LC3A/B, ATG12 and SQSTM1/?p62 protein in the brain tissues of each group were detected by Western Blot. Statistical analysis of experimental data was performed by t-test and one-way ANOVA.

Compared with the sham operation group (1.00±0.14) , the ATG12 mRNA level (5.23±0.37) in the brain of the HIE model group was significantly increased (t?= 33.60, P < 0.01) . Compared with the sham operation group[ (103.60±4.84) ?U/mgprot, (42.40±3.17) ?μmol/?mgprot], the SOD activity[ (62.60±3.44) ?U/mgprot] in the brain tissues of the HIE model group was significantly decreased, and the MDA content[ (83.80±4.39) ?μmol/mgprot]was significantly increased. Compared with the NC-HIE group[ (61.20±4.39) ?U/mgprot, (85.20±2.70) ?μmol/mgprot], the SOD activity[ (93.80±5.43) ?U/mgprot] in the brain tissues of the ATG12 shRNA-HIE group was significantly increased, and the MDA content[ (49.20±3.49) ?μmol/mgprot] was significantly decreased, and the differences were statistically significant (F?= 222.7, P?< 0.01; F?= 415.8, P < 0.01) . The results of Tunel showed that compared with the sham operation group, the level of brain tissues apoptosis in the HIE model group was significantly higher. Compared with the NC-HIE group, the brain tissues apoptosis level of the ATG12 shRNA-HIE group was significantly lower. Western Blot results showed that compared with the sham operation group (0.14±0.03, 0.13±0.02, 0.53±0.03) , the expression of ATG12 and LC3A/B protein (0.49±0.04, 0.45±0.03) in the brain of the HIE model group was significantly increased, and the expression of SQSTM1/p62 protein (0.24±0.03) was significantly decreased. Compared with NC-HIE group (0.46±0.03, 0.45±0.03, 0.25±0.03) , the expression of ATG12 and LC3A/B protein (0.13±0.02, 0.16±0.03) in the rat brain tissues was significantly decreased, and the expression of SQSTM1/p62 protein (0.53±0.04) was significantly increased, the difference was statistically significant (F?= 432.9, P?< 0.01; F?= 437.5, P?< 0.01; F?= 301.9, P?< 0.01) .

Inhibition of ATG12 expression can inhibit oxidative stress in mice, alleviate brain tissue apoptosis and autophagy levels in HIE mice, and inhibit brain damage.