Title : The establishment of an ideal animal model of POP and the mechanism of action of POP-related extracellular matrix proteins on the occurrence, development and reversal of POP
Abstract:
Objective: To establishment of an ideal animal model of POP and the mechanism of action of POP-related extracellular matrix proteins on the occurrence, development and reversal of POP.
Method: Thirty-six SD rats (female, 500-550g) were selected and after one month of adaptive feeding, they were evenly divided into four groups: the normal control group, the POP model group, the POP + TGF-β recombinant protein intervention group, and the POP + Fibulin5 recombinant protein intervention group. After the experiment, the rats in each group were sacrificed. The vaginal wall tissues of the rats were quickly dissected and then cut into small pieces (about 1 cm³) with scissors. One piece of tissue was placed in 10% neutral formalin at 4°C for overnight fixation for subsequent HE and Masson staining observation, and the remaining tissues were stored at -80°C for subsequent RT-PCR detection of the expression of POP-related extracellular matrix proteins in the vaginal wall tissues of each group of rats, and verified by WB experiment.
Results: 1.During the modeling stage, the height and diameter of the perineum and the length of the perineum significantly increased after daily modeling?Simulated birth injury?, and the vaginal wall was removed, but all the indexes of the animals recovered before the next day. On the second day of modeling, the vaginal wall of the animal was parallel to the vaginal opening. On the sixth day of modeling, the vaginal wall of the modeling animals was removed from the vaginal opening after the modeling operation. The MOPQ scores were 2-3 degrees prolapse.2. Compared with the blank control group, the expression of TGF-β, Fibulin-5, Lox and Elastin genes in the POP model group was significantly decreased, and the difference was statistically significant (P < 0.05). Compared with the POP model group, the expression of Fibulin-5 and Lox genes in the POP + TGF-β recombinant protein group was significantly increased; the expression of Fibulin-5 and Lox genes in the POP + Fibulin-5 recombinant protein group was significantly increased, and the difference was statistically significant (P < 0.05).
Conclusion: Mechanical damage can cause disordered arrangement of collagen fibers and smooth muscle tissues under the squamous epithelium of the vaginal wall, with focal smooth muscle rupture. In the model group, there is hyperplasia of collagen fibers under the squamous epithelium, disordered arrangement, reduction of smooth muscle bundles, partial rupture, and irregular arrangement. Inflammatory cell infiltration leads to a significant decrease in the expression of TGF-β, Fibulin-5, Lox, and Elastin genes, resulting in the occurrence of POP. After intervention with recombinant TGF-β or recombinant Fibulin-5, the expression levels of Fibulin-5, TGF-β, Lox, and Elastin genes are significantly increased, reversing the microenvironment of POP. This can be used as a new targeted treatment for the cause.
