Effect of Black Tea (Camellia sinensis) Extract on Thyroid Physiology During Pregnancy in Experimental Animal Model

Tea (Camellia sinensis) being the most consumed beverage worldwide. The safety evaluation of tea needs to be monitored during pregnancy, prenatal as well as postnatal developmental period beside its beneficial roles toward health and disease. Black Tea extract (BTE) may have an impact on thyroid hormone physiology and reproductive health during pregnancy. The objective of present study was to evaluate the role of BTE on thyroid physiology of pregnant rat during prenatal and postnatal period. Among three experimental groups, Group 1 was the control pregnant female rats respectively treated orally with saline, Group 2 and Group 3 were pregnant female rats treated with 50 mg and 100 mg BTE/kg body weight/day, p.o. respectively throughout prenatal and postnatal periods. All three groups of rats were provided balance diet and drinking water ad libitum. Animals were examined through their T3, T4, TSH, E2 and P4 hormone assay and histology of thyroid, ovary and uterus. All data were expressed as mean ± standard deviation with significance between the controls and the treated groups (n = 6). Experimental data were subjected to the ANOVA and Tukey test; P < 0.05 was considered as statistically significant. BTE treatment significantly increased the levels of T3 and T4 whereas decreased TSH level. BTE also alters the shape of thyroid follicles, follicular epithelium and colloid content in the lumen. This study confirmed BTE induced hyperthyroidism during pregnancy.