Table 2.

Effects of environmental chemical exposure on histological alterations indicating the risk of PCOS

S. No	Chemical name	Species	Dose	Route & exposure duration	Findings	References
1	BPA	Sprague Dawley rat	50 µg/kg/d	Subcutaneous injection (50 µg/50 uL PND1 to PND10)	Tremendous increase in the number of cysts, lesser number of corpora lutea, high number of atretic follicles (cystic), and lower antral follicles.	[34]
2	Lead acetate	BALB/c mice	30 mg/kg/d	Oral gavage (60 days)	Reduced primary follicular count, arrest in the growth and development of follicles.	[55]
3	Lead acetate	Adult Wistar rat	30,100, & 300 ppm	Drinking water (28 days)	Endometrium thickening, vacuolar degeneration in epithelial cells, narrow lumen, and degeneration of goblet cells.	[54]
4	Di (2-ethyl hexyl) phthalate (DEHP)	Mouse (CD-1) (transgenerational study)	Prenatal exposure of DEHP (0.05 mg/kg/d, 5 mg/kg/d) from gestational day 0.5-PND21 pups	Diet (chow)	Less number of primordial follicles (DEHP 0.05 mg/kg/d, 5 mg/kg/d) in the F1–F3 generations-more number of preantral follicles (DEHP 0.05 mg/kg/d, 5 mg/kg/d) in the F1–F3 generations. Less number of antral follicles in the F1 and F2 generations (DEHP 0.05 mg/kg/d). Decreased number of antral follicles (DEHP 5 mg/kg/d) in the F1 generation.	[61]
5	DEHP	CD-1 mice	20 & 200 µg/kg/d & 500 & 750 mg/kg/d	Oral (from gestational day 11 till birth)	In the F1 generation prenatal exposure causes a reduction in follicle numbers while in F2 and F3 generations rise in follicle numbers and increase in ovarian cysts.	[62]
6	Mercury	Wistar albino rat	1st dose 4.6 μg/kg/d & subsequent dose 0.07 μg/kg/d	Intramuscular injection (30 days)	Thickening of tunica albuginea in the ovaries, fibrils increased with connective tissues, congested capillaries and blood vessels. Oocyte and follicle borders were irregular. Thickening in uterine endometrium and myometrium areas.	[27]
7	Tributyltin and BPA	Sprague Dawley rat	TBT (10 & 100 ng/kg/d) BPA (50 μg/kg/d)	Subcutaneous injection daily from PND1-PND16	Decreased number of corpora lutea and antral follicles. Increased number of atretic follicles and presence of cysts.	[63]
8	Cadmium chloride (CdCl2)	Wistar rat	0.09 & 4.5 mg/kg	Oral gavage (90 days)	Cycle length prolongation, degenerated corpus luteum, and reduced number of oocytes.	[56]
9	Cd	Adult Wistar rat	CdCl2 (100 mg/L)	Oral with drinking water (30 days)	Reduced number of preantral follicles, antral follicles, and reduced granulose thickness.	[57]
10	CdCl2	Sprague Dawley rat	5 mg/kg	Oral gavage (6 weeks)	Higher number of antral and atretic follicles.	[35]
11	Polystyrene microplastics	Wistar rat	0.015 mg/kg/d, 0.15 mg/kg/d	Drinking water (90 days)	Thinning of granulose layer of secondary follicles and decreased number of growing follicles.	[64]
12	BPA	Wistar rat	50 & 500 µg/kg/d	Subcutaneous injection (21 days)	Development of cyst in ovarian follicles, loose attachment of theca cells, and necrosis.	[59]