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Fluoride is an essential trace element for humans and animals. Here, we explored the effects of sodium fluoride (NaF) on morphological, hormonal and histological changes in ovary of Asian stinging catfish Heteropneustes fossilis (Bloch) after exposure to 1/10th mg and 1/5th mg F/L of LC50 of fluoride in water for 45 and 90 days. Activities of follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and estradiol (E) were measured using an enzyme-linked immunosorbent assay. Histological evaluation of the ovaries was conducted after staining with haematoxylin-eosin (HE). Reproductive hormones were significantly decreased after NaF-treated groups. Ovary was found to be adversely effected by exposure to NaF. Maturation of follicles was inhibited by exposure after observation of GSI and histology in ovary. These results suggest that female reproductive system is adversely affected by NaF. NaF may thus significantly reduce the fertility of female fish. This study encompasses alteration in hormonal assay to evaluate the role of vitamins C in the recovery of fluoride toxicity in fish. Vitamin C is a water-soluble ROS scavenger with high potency. [ABSTRACT FROM AUTHOR]

The present study highlights fluoride -induced toxicity and the protective role of ascorbic acid in the liver and ovary of freshwater fish, Heteropneustis fossilis. The fish specimens were exposed to different concentrations (35 mg F/L and 70 mg F/L) of fluoride. Parameters related to oxidative stress were studied at the end of the experiment. The biomarkers selected for the study were thiobarbituric acid reactive substances for assessing the extent of lipid peroxidation (LPO) and antioxidant defense system such as reduced glutathione (GSH), superoxide dismutase (SOD) catalase (CAT) glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities. The fluoride exposure significantly elevated the level of LPO, CAT, SOD, and GST in the tissues of treated group as well as modulated the activities of GSH and level of GPx after exposure as compared to the control. A significant decrease in GPx activity was found in these tissues suggesting that fluoride exposure increases the level of free radical, as well as CAT activity. Pre- and post treatment with ascorbic acid decreased the LPO, SOD, CAT, GST level, and increased GSH, GPx levels in the liver and ovary.

Effect of various concentrations of nickel (100, 200, 500 and 1000 microM) and recovery treatments of boron (50 and 100 microM) and copper (15 and 75 microM) each with 200 microM and 500 microM of nickel on germination, growth, biomass, chlorophyll, carotenoids, pheophytin, amylase, protein, sugar as well as activity of catalase and peroxidase were studied in radish (Raphanus sativus cv. Early menu) seedlings. Nickel treatments caused a considerable reduction in germination percentage, growth and biomass. The different pigments were also decreased with nickel treatments. However boron addition with nickel recovered the negative effect on pigment contents. Among biochemical estimations, amylase activity and total proteins were found to be reduced in nickel treatments. Peroxidase and catalase activity were induced other than higher total sugar with nickel treatments. The combination of nickel with boron resulted into increased protein contents. This combination also reduced the catalase and peroxidase activity. The influence of nickel with copper failed to produce significant recovery except 200 microM nickel in combination with 15 microM copper with regard to catalase and peroxidase activity. The effect of nickel on hydrolyzing enzyme amylase was observed to be inhibitory resulting into poor germination followed by poor seedlings growth. The stress protecting enzymes peroxidase and catalase seem to be induced under the influence of nickel, and providing protection to the seedlings. The application of boron with nickel showed improved germination and growth. The level of catalase and peroxidase were found to be significantly reduced showing normal growth and biomass of seedlings.