Photobiomodulation can improve ovarian folliculogenesis and steroidogenesis in polycystic ovary syndrome‐induced rats

Abstract

Photobiomodulation (PBM) has been investigated and used in clinical practice, related to biomodulatory influences on cellular functions in animals and humans. The absorption of photons by the photoreceptors causes changes in the molecular configuration of these receptors and activate molecular signals in the cells. Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorder in women of reproductive age, and it has a prevalence of 2% to 27%. Diagnosis of PCOS requires two of the following: polycystic ovaries, hyperandrogenism, and oligomenorrhea or amenorrhea. The cause of PCOS is still unknown and animal models PCOS‐induced are important tools for understanding the pathophysiology of the syndrome. We aimed to analyze the PBM effects on follicle and cyst numbers, and ovarian testosterone (T) synthesis in a rat PCOS model induced by estradiol valerate (EV). Twenty adult Wistar rats (n = 5 per group) were divided into control (C), PCOS, PBM, PCOS/PBM groups. PCOS was induced by single injection of EV (2 mg/kg/bw/i.m.). The animals were irradiated with a laser (wavelength 808 nm, power 60 mW), using a dose of 1 Joules(J)/point on each ovary, 3 times weekly, totaling 2 J of energy for each irradiated animal per day of application. The animals were evaluated 30, 45, and 60 days after treatments. After sacrifice, plasma T was determined, and the ovaries were collected and prepared for histological analysis. Statistical analysis: ANOVA and Fisher's test. The results were reported as means ± SD. This study was approved by the local Animal Care and Use Committee (protocol n° 030/2016). T: PCOS group: The 60‐day (1.075 ± 0.612 pg/mL) and 45‐day (0.049 ± 0.0465 pg/mL) groups showed increased T, compared to the 30‐day (0.01568 ± 0.00869 pg/mL). PCOS/PBM group: The 60‐day (0.2653 ± 0.1706 pg/mL) and 45‐day (0.04136 ± 0.01667 pg/mL) groups showed increased T, compared to the 30‐day (0.04172 ± 0,01875 pg/mL). After 60 days of treatments, the C (0.1062 ± 0.0988 pg/mL) and PBM (0.0836 ± 0.1706 pg/mL) groups presented lower T, compared to PCOS (1.075 ± 0.612 pg/mL) and PCOS/PBM (0.2653 ± 0.1706 pg/mL) groups. Ovaries: the highest number of follicular cysts (6.33 ± 1.52) occurred in the PCOS group 60 days after EV injection, while the lowest number of follicular cysts was observed in the C group (0.33 ± 0.57). The 60‐day PCOS/PBM group presented fewer (3 ± 1) follicular cysts than the PCOS group, but more follicular cysts than the C group. The highest number of follicles was observed in 30‐day C (8 ± 1) group, while the lowest number was observed in the 60‐day PCOS (1.66 ± 0.57) group. The number of follicles found for the 60‐days PCOS/PBM (6.66 ± 0.57) group was higher than for the PCOS group and equal to the C group. It could be concluded that the PBM reduced plasma T of the PCOS group, decreased the number of follicular cysts and increased the number of ovarian follicles in the PCOS/PBM group, compared to the PCOS group, apparently restoring the ovarian folliculegenesis and steroidogenesis activities.Support or Funding InformationFAPESP (Grant 2016/02811‐4)