Table 1.

The pathological scoring standard.

Score	Pathological changes
0	The intestinal mucosa and villi were complete; the structure was completely normal
1	Slight submucosal and/or lamina propria separation
2	Moderate submucosal and/or lamina propria separation; submucosal and/or muscular layer edema
3	Severe submucosal and/or lamina propria separation; submucosal and/or muscular layer edema; local intestinal villi shedding
4	Intestinal villus disappearance with intestinal necrosis