Ovarian p75NTR mRNA and protein expression. As shown in panel A, ovarian p75NTR mRNA was found unchanged in the PCO group compared to the control and EA group. Low-frequency EA treatments did not significantly affect ovarian p75NTRmRNA expression in the EA, PCO and PCO+EA groups. Values are given as means ± SEMs normalized to GAPDH. As shown in panel B, the number of ovarian p75NTR immunopositive cells was significantly decreased in the EA group when compared to controls. The number of p75NTR-stained cells in the PCO group was significantly higher than in controls, while repeated EA treatments greatly decreased p75NTR protein immunoreactivity in the PCO+EA group. Values are given as means ± SEMs. ap < 0.05 vs control group. bp < 0.05 vs PCO group. Representative pictures of stained cells (pointed by black arrows) are showed in Panels C-D. The p75NTR was found expressed in the thecal layer of healthy follicles (C) and in the stromal region (D) in all of the experimental groups. Magnification C-D: ×200.