Examination and comparison of the effects of vitamin c replacement and platelet-rich plasma application on the pelvic floor in rats with birth trauma at the level of light and electron microscopy

Aim: To histologically observe and compare the separate and combined effects of vitamin C and PRP application on the healing process of the vagina and surrounding connective tissues after pelvic floor injury. Materials and Methods: 30 nulligravid Wistar-Albino rats were divided into 5 groups and all of them, except the PRP Donor group (Control group), were simulated with vaginal birth with vaginal distension under anesthesia. The 16 Fr Foley catheter was inflated with 8 ml of air and waited for 5 hours, then the balloon was withdrawn from the vagina without deflating. Subsequently, the experimental group was followed for 30 days with ad libitum feeding at the Experimental Animal Unit of Ankara University, and no additional treatment was applied to the experimental group. In the vitamin C replacement group, vitamin C was added to the drinking water at a dose of 1.25 mg/ml/day, to be renewed daily, for 30 days. In the PRP injection group, a total of 1 ml of PRP was injected subcutaneously at the 3-9 o'clock position immediately after the balloon in the vagina of each rat was removed, and no additional action was taken. In the vitamin C + PRP injection group, both PRP injection and oral vitamin C replacement were administered for 30 days. The PRP Donor group was used to obtain PRP while under anesthesia and as a control group for intact rat vaginal tissue examination. At the end of the 30-day follow-up, 4 groups were euthanized by CO2 inhalation. The vaginal and paravaginal areas of all rats were dissected and placed in neutral formalin and glutaraldehyde solutions to be examined under light and electron microscopy and sent to Ankara University, Department of Histology and Embryology. Then, they were stained with Hematoxylin & Eosin, Masson-Trichrome and Van-Gieson tissue stains, and thin sections were taken and examined. Evaluation was made by looking at the thickness and morphology of the vaginal epithelium, the distribution and morphology of collagen-elastic fibers, the structure of the muscular layer and the presence of keratohyalin granules. Results: It has been histologically proven that damage to the pelvic floor is caused by birth trauma caused by vaginal distension. The difference between groups in terms of epithelial thickness was found to be significant (p<0.001). When looking at the paired groups, the differences between the experiment-vitamin C replacement, experiment-vitamin C replacement + PRP injection, experiment-PRP donor and PRP injection-PRP donor groups were significant (p=0.043, p=0.035, p<0.001 and p=0.006, respectively). The average epithelial thickness of the experimental group was 31.07±0.42, 70.85±1.11 in the vitamin C replacement group, 68.08±1.46 in the PRP injection group, 70.93±0 in the vitamin C replacement + PRP injection group, It was measured as 97 and 75.85±0.97 in the PRP donor (control) group. The difference between the five groups in terms of the percentage area of collagen fibers was found to be significant (p<0.001); The highest mean was found in the vitamin C replacement group, while the lowest mean was found in the experimental group. The differences between the experimental-vitamin C replacement, experimental-PRP donor and PRP injection-vitamin C replacement groups were significant (p<0.001, p=0.001 and p=0.023, respectively). The difference between groups in terms of the presence of structural deterioration in the muscular layer was significant (p = 0.004). At the end of the study, while the rate of continuation of the initial deterioration remained unchanged in the experimental group, it was observed as 16.7% in the vitamin C group, 33.3% in the PRP injection group, and 33.3% in the vitamin C + PRP injection group. There was no structural deterioration in the PRP donor group. There was no significant difference between the groups in terms of the presence of keratohyalin granules (p = 0.180). 33.3% in the experimental group; 83.3% in the vitamin C group; It was observed at a rate of 66.7% in the PRP injection group and 66.7% in the vitamin C + PRP injection group. Keratohyalin granules were seen in all rats in the PRP donor group. Electron microscopy imaging was also observed to be consistent with the data obtained. Conclusions: Birth trauma caused by vaginal distension has serious effects on the pelvic floor. Thinning and irregularity in epithelial thickness, percentage differences in collagen fiber distribution, and structural deterioration in the muscular layer have demonstrated this. Findings regarding the presence of keratohyalin granules reflect changes at the cellular level. Vitamin C and PRP application had a positive effect on the healing process after damage to the pelvic floor, and vitamin C was determined to be more beneficial than PRP. It is necessary to confirm these results and develop advanced treatment options with subsequent clinical and experimental studies.