Effects of Fluoride Ingestion with Protein Deficient or Protein Enriched Diets on Sperm Function of Mice

The effects of ingestion of protein deficient or protein supplemented diets with or without sodium fluoride (NaF, 5, 10, and 20 mg/kg body wt) were studied on sperm function in mice and compared with effects on mice fed a control (standard) protein diet + NaF in the above three dose levels for 30 days. Ingestion of the protein deficient diet together with the three dose levels of NaF caused a significant decrease in sperm motility, sperm count, sperm viability, fertility rate, sperm mitochondrial activity index (SMAI), number of normal spermatozoa, and hyaluronidase activity. However, DNA integrity, assessed by acridine orange fluorescence staining, and total acrosin levels, for acrosome integrity, were comparatively less affected. The control protein diet plus the three dose levels of NaF also caused significant alterations in all these parameters as compared to control Group I. However, mice fed a protein supplemented diet with or without the three doses of NaF did not manifest any changes, and the above parameters in them were almost the same as in control Group I. The decrease in sperm motility appears to be related to decline in SMAI and abnormal sperm counts. The significant decrease in sperm viability along with the above parameters would be expected to affect fertility, whereas inhibition of hyaluronidase and to some extent of acrosin could affect fertilizing capacity of the sperm. The results reveal that dietary factors such as increased protein intake can be especially valuable in curbing fluoride fertility toxicity.