This study compared the modeling effects of a rat internal hemorrhoid model with the croton oil-induced acute hemorrhoid model of rat. A total of 48 SPF-grade SD rats were randomly divided into a control group and model group, with 24 rats in each. The model group used croton oil mixture to induce and combined with both standing posture and swimming movement to establish the model, with a modeling time of 1 week; the control group used croton oil mixture for induction. Observations were made on the symptoms and signs at 6 h and 1, 3, and 7 days post-modeling. Anorectal coefficient measurement, histopathological analysis, laser speckle contrast imaging, reverse transcription quantitative polymerase chain reaction (RT-qPCR), immunohistochemical (IHC), and western blotting were used to evaluate the outcomes of different modeling methods. In contrast to the control group, the model group exhibited a more obvious degree of organ swelling, accompanied by a greater degree of rectal prolapse and an increase in the anorectal coefficient. Under microscopic examination, the model group demonstrated severe epidermal cell death and significant blood vessel congestion. Laser speckle contrast imaging revealed that the model group exhibited increased rectal blood perfusion with enlarged capillaries. The model group showed higher relative mRNA levels of interleukin (IL)-2, IL-6, and tumor necrosis factor alpha (TNFα) at all time points, along with elevated protein levels of these cytokines. The rat internal hemorrhoid model demonstrated modeling effects more aligned with clinical features of internal hemorrhoids. The model is a better option for research purposes in the development of treatments for hemorrhoids compared to the croton oil-induced acute hemorrhoid model.
Sun et al. (Thu,) studied this question.