Histopathological and Follicular Atresia Assessment of Rat’s Ovarian Tissue Following Experimental Chronic Spinal Cord Injury

Background: One of the important side effects in spinal cord injuries in both genders is sexual dysfunction. This study aimed at investigating histopathological changes of ovaries in the chronic phase after spinal cord injury. Methods: Animals (adult female rats) were divided to the following groups, Control (Co), Sham (Sh), and Spinal Cord Injury (SCI); each group contained 18 rats. The spinal cord of SCI animals was transected by the bilateral laminectomy method on level T9, while the rats of the sham group were incised in the same location without any spinal cord injury. Animals were sacrified at 7th, 14th and 21st day postsurgical intervention, then the body weight, and the weight and volume of ovaries were measured. The slices were stained by hematoxylin and eosin and periodic acid Schiff methods. The histomorphometric changes of the diameter of the follicle and ovum, and the thickness of granulosa layer were measured in different kinds of follicles including, Unilaminar Primary Follicle (UPF), Multilaminar Primary Follicle (MPF), Secondary Follicle (SF), and Tertiary Follicle (TF). Results: The results showed that the animal weights were decreased in three SCI groups (P = 0.018). In the SCI groups, the diameter of follicle and ovum and the thickness of granulosa layer were significantly decreased in different kinds of follicles (P = 0.012). Also the thickness of zona pellucida and theca interna were significantly decreased in UPF, SF, and TF in the SCI groups on 14th and 21st day (P = 0.024). The histopathologic examination revealed widespread ovarian follicle atresia in the SCI groups on the 14th and 21st day, including numerous cell debris and inflammatory cells in the antrum atretic follicles. The ovarian stroma showed edema, fibrosis, hypercellularity, and vasodilation in the SCI group, compared to the sham or control groups. Conclusions: The histopathlogic data indicated that after spinal cord injury many histologic parameter changes occurred and hetrogenity of ovarian structure increased. These changes may be caused by dysfunction of the autonomic system and the modification in amount of the ovarian neurotransmiters.