OBJECTIVE To probe into the protective effects of polydatin on hyperoxic lung injury through the expression of SPOCK2 in neonatal mice. METHODS: Normal lung epithelial cells mlE-12 in mice were cultured in vitro and set as the control group; mlE-12 cells were stimulated with hyperoxia and set as the hyperoxia group. The mlE-12 cells were treated with 50

100 and 150 μmol/ml of thujaplicin

and then stimulated with hyperoxia

which were set as the hyperoxia + low dose group

hyperoxia + medium dose group and hyperoxia + high dose group

respectively. The pcDNA and pcDNA-SPOCK2 were transfected into mlE-12 cells

which were stimulated with hyperoxia and set as hyperoxia + pcDNA group and hyperoxia + pcDNA-SPOCK2 group. The si-NC and si-SPOCK2 were transfected into mlE-12 cells

then stimulated with hyperoxia and treated with high dose（ 150 μmol/ml） of thujaplicin

which were set as hyperoxia + high dose + si-NC group and hyperoxia + high dose + si-SPOCK2 group.Malondialdehyde（ MDA） content and superoxide dismutase（ SOD） activity were detected by chemical method; tumor necrosis factor α（ TNF-α）

interleukin-1β（ IL-1β） and interleukin-6（ IL-6） content were detected by enzyme-linked immunosorbent assay. Real-time fluorescence quantitative polymerase chain reaction was used to detect SPOCK2 mRNA expression. Expression of SPOCK2 protein was detected by protein blotting. RESULTS: Compared with the control group

the MDA content increased significantly and SOD activity decreased significantly in the hyperoxia group; compared with the hyperoxia group

the MDA content decreased significantly and SOD activity increased significantly in the hyperoxia + low dose group

hyperoxia + medium dose group and hyperoxia + high dose group

with statistically significant differences（ P<0. 05）. Compared with the control group

the levels of TNF-α

IL-1β and IL-6 increased significantly in the hyperoxia group; compared with the hyperoxia group

the levels of TNF-α

IL-1β and IL-6 decreased significantly in the hyperoxia + low dose group

hyperoxia + medium dose group and hyperoxia + high dose group

with statistically significant differences（ P<0. 05）. Compared with the control group

the SPOCK2 mRNA and protein expression decreased significantly in the hyperoxia group; compared with the hyperoxia group

the SPOCK2 mRNA and protein expression increased significantly in the hyperoxia + low dose group

hyperoxia + medium dose group and hyperoxia + high dose group

with statistically significant differences（ P < 0. 05）. Compared with the hyperoxia + pcDNA group

the MDA content

levels of TNF-α

IL-1β and IL-6 decreased significantly and the SOD activity increased significantly in the hyperoxia + pcDNA-SPOCK2 cells; compared with the hyperoxia + high dose +si-NC group

the MDA content

levels of TNF-α

IL-1β and IL-6 increased significantly and SOD activity decreased significantly in the hyperoxia + high dose + si-SPOCK2 group

with statistically significant differences（ P < 0. 05）.CONCLUSIONS: Polydatin can inhibit hyperoxic lung injury in neonatal mice through up-regulating the SPOCK2 expression

which has protective effects for lung tissues.