Objective To explore the preparation process of frozen sections of mouse spinal cord injury model based on coronal partitioning sequential serial sectioning.

Methods Specific pathogen free (SPF)-grade C57BL/6J mice, aged 8-10 weeks, were used to establish mouse spinal cord injury models. Mouse models successfully established at 7 d after injury were assigned into the 7dpi group (n = 10) and mice receiving sham operation were assigned into the Sham group (n = 10). The injured spinal cord tissues were dehydrated and embedded, and tissue sections were obtained by partitioning sequential serial sectioning. Hematoxylin-eosin (HE) staining, Masson staining and histoimmunofluorescence staining were performed. At postoperative 7 d, the recovery of motor function of mice in two groups was assessed by Basso Mouse Scale (BMS) score. The BMS scores between two groups were compared by Mann-Whitney U test.

Results Ten mouse models of contusion spinal cord injury were successfully established. Bilateral lower limb paralysis was observed. Motor function recovery analysis showed that the score in the 7dpi group was 2(2, 3), significantly lower than 9(9, 9) in the sham group (U = 0, P ＜ 0.001). HE staining and Masson staining were used to label the tissues, and staining results showed that the injured areas were found in the I, J, a, b and c spinal cord tissues in the 7dpi group.

Conclusions  The partitioning sequential serial sectioning proposed in this study serves an efficient and stable histological method for the study of spinal cord injury, which not only assists in-depth analysis of pathophysiological changes during the process of spinal cord injury, but also can be applied in analyzing other multi-layer structures.