IN MICE WITH GENETICALLY-INDUCED MITOCHONDRIAL DYSFUNCTION AND INFERTILITY, INTRAOVARIAN PLATELET RICH PLASMA (PRP) INJECTION DOES NOT IMPROVE REPRODUCTIVE PARAMETERS

Caseinolytic peptidase P (Clpp), mitofusin 1 (Mfn1), and mitofusin 2 (Mfn2) are genes required for oocyte mitochondrial function and dynamics (fusion/fission). Mice with global germline deletion of Clpp and oocyte-specific deletion of Mfn1 and Mfn2 show mitochondrial dysfunction, female infertility associated with impaired oocyte maturation and follicle development, and a phenotype consistent with accelerated ovarian aging. Recently, intraovarian platelet rich plasma (PRP) injection has been used as a treatment for follicular activation in women with premature ovarian insufficiency (POI) and poor ovarian response (POR). However, ovarian effects of PRP have not yet been elucidated in experimental models. In this study, we aimed to determine if intraovarian PRP injection increases oocyte and embryo yield in mouse with targeted deletion of Clpp, Mfn1, or Mfn2. 8-week-old female Clpp-/- (n=11), Mfn1-/- (n=6), Mfn2-/- (n=12) and wild-type (WT, n=12) mice were randomized to receive intraovarian PRP or sham injection with saline. PRP was isolated of blood obtained from retro-orbital vein by centrifugation at 1500 rpm for 8 minutes, followed by centrifugation of the plasma supernatant at 2000 rpm for 15 min to concentrate the platelets. Fourteen days after injection, mice were stimulated with 10 UI PMSG followed by 10 IU of human chorionic gonadotropin (hCG) 48 h later and mated with wild type males with proven fertility, as indicated. Mature oocytes (metaphase II [MII]) and 2-cell embryos were collected from the oviducts 14 and 42 hours after the hCG injection, respectively. Follicle development was assessed in serial ovarian sections stained with hematoxylin and eosin (n=3 per group and treatment). Primordial, primary, secondary, early antral and antral follicles were individually quantified. ANOVA and Student’s t-test were used for statistical analyses. In the Clpp-/- model, PRP injection did not improve the number of MII oocytes (10.1 ± 6.9 vs 16.5 ± 0.7; p = ns) or 2-cell embryos (4.5 ± 3.7 vs 9.0 ± 1.4; p = ns), compared to controls. Similarly, in the Mfn2-/- model, PRP injection did not modify the number of MII oocytes (3.0 ± 2.8 vs 0.25 ± 0.5, p = ns) or 2-cell embryos collected (0.5 ± 0.7 vs 0 ± 0, p = ns). In the Mfn1-/- model, which has a more severe infertility phenotype and does not generate mature oocytes or embryos, the injection of PRP did not result in an improvement. No significant difference was found in the number of follicles at different stages of development between Clpp-/-, Mfn1-/-, Mfn2-/-, mice injected with PRP, compared to controls. Intraovarian PRP injection does not improve ovarian function or fertility in mice with targeted deletion of mitochondrial function genes.