Platelet-rich Plasma (PRP) Gives Beneficial Effects on the
thin Endometrium as Well as Increases Endometrial
Regeneration in Rat

Hang Yong Jang¹, Soo Min Myoung², Jeong-Min Choe², Yong Min Kim³,
Tak Kim¹, Hyun Tae Park¹

¹Department of Obstetrics and Gynecology, Korea University Anam Hospital, Korea University College of Medicine,
²Department of Biomedical Sciences, Korea University College of Medicine,
³Department of Obstetrics and Gynecology, Bundang CHA General Hospital, CHA University College of Medicine

Background & Objectives: Women presenting with thin endometrium/Asherman’s syndrome refractory to estrogen treatment have not only been an intractable problem in ART, but also presented various clinical symptoms of amenorrhea, hypomenorrhea, or recurrent pregnancy loss. This thin endometrium is usually characterized by poor growth of the glandular epithelium with little stroma, intrauterine adhesions or fibrosis, and poor vascular development. We investigated whether platelet-rich plasma (PRP) treatment can improve the regeneration of endometrium in an experimental model of thin endometrium.

Method: A total of 60 female adult Sprague Dawley rats were divided into three groups (control group I: submitted to injection of physiological saline in the uteri horn; non-PRP treated group II: submitted to injection of 95% ethanol into the uterine horn to damage without PRP treatment; PRP-treated group III: administrated with PRP, 72 hours after damage). After 9 days of post-modeling, all rats were injected intramuscularly with pregnant mare serum gonadotrophin (PMSG) and, after 55 hours, the samples were collected on the estrous cycle, which were also confirmed by vaginal smears. Endometrial morphology and fibrosis were analyzed by hematoxylin-eosin staining (H&E) and Masson Trichrome, and the growths of the epithelial, stromal and vascular cells were evaluated by immunohistochemistry (IHC) with cytokeratin, Hoxa10, VEGF, and Ki-67, followed by western blot testing. The expression of IL-1b, IL-10, c-kit (CD117), and Oct-4 were evaluated at the messenger RNA (mRNA) level by real-time PCR assays.

Results: We found that endometrial thickness and morphology presented a significant difference between the PRP-treated group and the non-PRP group. The PRP-treated group showed a significant increase in the area of endometrium compared with the non-PRP group (P<0.05). Trichrome staining confirmed significantly decreased fibrosis in the PRP-treated group compared to the non-PRP group (P<0.05). Though IHC, there was a significantly stronger expression of cytokeratin, Hoxa10, VEGF, and Ki-67 in the PRP-treated group than the non-PRP group. The western blotting results also correlated well with IHC staining intensity on the markers of Hoxa10 and VEGF. Both IL-10 and IL-1b mRNA were significantly up-regulated in both the RPR/non-PRP groups compared with the control group. The stem cell makers, Oct-4 and c-kit mRNA, were significantly up-regulated in the PRP-group compared with the non-PRP group.

Conclusions: Experiments using this thin endometrial model demonstrated that autologous PRP not only can stimulate and accelerate the regeneration of the endometrium but also decrease in the level of fibrosis. These results also suggest that PRP may enhance proliferation of the progenitor stem cells reside in the uterus and showed a potential novel treatment for preventing Asherman’s syndrome after uterine injury as well as thin endometrium refractory to estrogen treatment.

This research was partially supported by the National Research Foundation of Korea (NRF) (R1304231).