Lıght microscopical histological and electron micrographic strucure of ovary of 4 mg/L TiO2 exposed group. A, cytoplasmic vacuolization (red arrow) at follicular epithelium and ooplasm; b, multilamellar vesicle and cytoplasmic vacuolization (star); c, mitotic catastrophe; d, altered mitochondrium morphology and loss of cristae organization; e, cytoplasmic vacuolization (star) and multilamellar vesicle; f, dispersion at ooplasm; g, degenerated vitellogenic oocyte; h, unification of cortical alveoli (asterix). ZR, zona radiata; Fe, follicular epithelium; M, mitochondrium; ML, multilamellar vesicle; RER, rough endoplasmic reticulum; Ve, vitelline envelope; Vo, vitellogenic oocyte; N, nucleus; CoC, cortical alveolus stage; Om, mature oocyte. Magnification: g, h, x20.