Sodium fluoride adversely affects ovarian development and reproduction in Drosophila melanogaster

- Chronic sub-lethal exposure to NaF (10-100 μg/mL) reduces fecundity in Drosophila.
- NaF exposure leads to altered adult body size and larval weight in fruit flies.
- NaF associated alterations in ovarian architecture and germ cell viability observed.
- NaF induces DNA fragmentation and changes in G6PD, CAT, LPO activities in ovary.
- NaF exposure at 10 and 20 μg/mL increases DNA damage in fat body cells.

The study demonstrates the effects of chronic sub-lethal exposure of sodium fluoride (NaF) on reproductive structure and function of female Drosophila melanogaster. As a part of treatment, flies were maintained in food supplemented with sub-lethal concentrations of NaF (10-100 μg/mL). Fecundity, ovarian morphology, presence and profusion of viable cells from ovary and fat body were taken into consideration for evaluating changes in reproductive homeostasis. Wing length (a factor demonstrating body size and reproductive fitness) was also monitored after NaF exposure. Significant reduction in fecundity, alteration in ovarian morphology along with an increase in apoptosis was observed in treated females. Simultaneous decline in viable cell number and larval weight validates the result of MTT assay. Furthermore, altered ovarian Glucose-6-phosphate dehydrogenase and catalase activities together with increased rate of lipid peroxidation after 20 and 40 μg/mL NaF exposure confirmed the changes in reproduction related metabolism. Enhanced lipid peroxidation known for ROS generation might have induced genotoxicity which is confirmed through Comet assay. The enzyme activities were not dose dependent, rather manifested a bimodal response, which suggests a well-knit interaction among the players inducing stress and the ones that help establish physiological homeostasis.

Schematic representation of the findings of the entire study, Study demonstrates that, NaF at sub-lethal concentrations has negative impact on reproductive homeostasis of Drosophila melanogaster. The stress caused from NaF exposure might be the underlying cause of reduced fecundity, altered ovary structure, DNA damage, reduced availability of viable germ cells, and fat cells, and alteredenzyme activity in comparison to the control category.85