Objective To conduct the reductive reservation for torsional ovary in different states(.un-necrotic ovary,suspected necrotic torsional ovary and torsional necrotic ovary)after the ovarian torsion in pre-maturity SD rat,and to investigate its effect on the ovarian reproductive function in maturity stage.Methods A total of 32 SD rats with 3 weeks old were selected and randomly divided into 4 groups,8 cases in each group.The animal model of ovarian torsion was made by using the Turner method,which was similar to the animal model of testicular torsion,and either group was selected to undergo the sham operation as the con-trol group(CG group).The non-necrotic torsional ovary detorsion group(NNTOD group),suspected necrotic torsional ovary detorsion group(SNTOD group)and necrotic torsional ovary detorsion group(NTOD group)were established respectively.When the animals were fed to sexual maturity at 8 weeks of age,the experimen-tal animals were sacrificed by vertebral dislocation method,and the ovary tissues on the torsional side were cut for HE staining and transmission electron microscopy to examine the changes of ovarian histomorphology and mitochondrial structure.Ovarian cell apoptosis was detected by Tunel assay.ELISA method was used to de-tect the follicle-stimulating hormone(FSH),luteinizing hormone(LH)and anti-mullerian duct hormone(AMH)levels in centrifugal blood.Results The ovarian structure in the CG group and NNTOD group was clear,the ovarian follicles at different levels were developed well;the electron microscopy showed normal mi-tochondria.The ovarian partial structure in the SNTOD group was disorganized,the number of follicles at all levels of growth was decreased;electron microscopic examination showed a little damage of mitochondria.In the NTOD group,the arrangement of ovarian structure was obviously disordered,the number of growing folli-cles at all levels was significantly reduced;the electron microscopy showed that most of the mitochondria were obviously swollen and severely damaged.Compared with the CG group,the apoptosis rate in the SNTOD group and NTOD group was significantly increased(P＜0.05).There was no statistically significant differ-ence between CG group and NNTOD group(P＞0.05).Compared with the NTOD group,the apoptosis rate in the SNTOD group was decreased(P＜0.05).Compared with the CG group,the levels of LH and FSH in the SNTOD and NTOD groups were increased,and the AMH level was decreased(P＜0.05).The LH and FSH levels in the SNTOD group were lower than those in the NTOD group,the AMH level was higher than that in the NTOD group(P＜0.05).Conclusion After reduction of the torsional suspected necrotic ovary in the prematurity rat,the ovarian reproductive function in the torsional side during sexual maturity period is slightly injured;while after reduction of torsional necrotic ovary restoration,its reproductive function is appar-ently damaged.