| Abstract: | Objective To find out the more stable rat models of intrauterine adhesions, so as to provide the basis for further investigation into the mechanism of intrauterine adhesions occurrence and exploration of novel treatments by constructing rat models of intrauterine adhesions with different measures. Methods Forty-eight female SD rats in estrus were randomly assigned to one of the four groups: control group, lipopolysaccharide cotton thread group （with line group）, lipopolysaccharide injection group （injection group）, lipopolysaccharide gelatin group （gelatin group）, each group consisted of 12 rats. Rats in the gelatin group placed a gelatin sponge strip soaked in lipopolysaccharides in the uterine cavity after curettage. In each group, 4 rats were sacrificed 7 days, 14 days, and 28 days later, respectively, and endometrial tissue was detected, the number of endometrial glands and the area of fibrosis of the rats were observed by HE staining and Masson staining and the expression of the fibrotic protein TGF-β1 was detected by immunohistochemistry. Western Blot was used to detect the protein expression of fibrotic proteins Collagen-I, Collagen-III, α-SMA, and TGF-β1. Result （1） The results of HE staining showed that the number of glands in each group decreased compared with the control group after 7 days, 14 days, and 28 days of modeling （P < 0.05）. Of these, after 14 days and 28 days of modeling, the number of glands in the injection group decreased more significantly than those in the line and gelatin e group （P < 0.05）, and when modeling for 28 days the number of glands in the injection group was close to zero. （2） Masson staining showed that the degree of fibrosis of the endometrium in the lineage-based group, injection group, and gelatin group was significantly higher than that of the control group at 7 days, 14 days, and 28 days （P < 0.05）, and after comparison between different groups, it was found that the degree of endometrial fibrosis of rats in the injection group was higher than that in the line-and-line group and gelatin group （P < 0.05）, and the injection group after 28 days of molding was the most severe group. （3） Immunohistochemical staining showed that TGF-β1 expression in the lineage group, there was a significant increase in the injection group and gelatin group compared to the control group at 7 days, 14 days, and 28 days of modeling, and the differences in the other groups were statistically significant with the exception of the line and gelatin group for 7 days of molding （P < 0.05）. Furthermore, at 7 days and 28 days after modeling, TGF-β1 expression in the injection group was greater than that in the gelatin group （P < 0.05）. （4） Western blot analysis showed that the expression of fibrosis related proteins was up-regulated by different methods of infective bacterial lipopolysaccharide treatment after mechanical injury, and upon a comparison between different groups, it was found that the expression of Collagen-I, Collagen-III, α-SMA, and TGF-β1 in the injection group was increased in comparison to that in the gel-treated group （P < 0.05）, but the difference between the gelatin e group and the strip group did not reach statistical significance （P > 0.05）. After 7 days of molding, the expression Collagen-I, Collagen-III And α-SMA in the injection group was higher （P < 0.05）, 14 days after molding, the expression of Collagen-III andα-SMA （P < 0.05） in the injection group was higher than that in the line group, and the expression of Collagen-I, Collagen-III, α-SMA, and TGF-β1 in the injection group was greater （P < 0.05）. The expression of Collagen-I, Collagen-III, α-SMA and TGF-β1 protein in the control group, the line group, the injection group, and the gelatin group was the highest, and after mechanical injury, the effect of lipopolysaccharide injection to damage the uteri of rats was the most significant. Conclusions The rat model of intrauterine adhesions obtained by intrauterine injection of lipopolysaccharide after curettage is more severe than that obtained by intrauterine placement of a cotton string of lipopolysaccharide or lipopolysaccharide gelatin and the rat model of intrauterine adhesions has the most severe damage 28 days after modeling. The placement of lipopolysaccharide gelatin in the uterine cavity following curettage is a novel method that may also result in intrauterine adhesions. |
