Management of fluoride induced testicular disorders by calcium and Vitamin-E co-administration in the albino rat

Effects of fluoride toxicity on the male reproductive system: A review

BACKGROUND

Fluoride toxicity and fluorosis is an emerging global problem. Fluoride has long been added to water for dental caries prevention; however, it has a variety of damaging consequences on human bodies. The aim of this paper is to analyse all the literature available on the effects of fluoride toxicity on male reproductive system.

METHODS

Research papers were collected using various methods of data collection like Pubmed, Scopus, and Google Scholar from 1980 to 2024, and then reviewed thoroughly.

RESULTS

Fluoride is known to cause various histopathological and biochemical alterations in the male reproductive system. It also affects fertility, semen quality, sperm number and quality,the process of spermatogenesis and spermiogenesis. Key changes caused by fluoride in male reproductive system include structural defects in the flagellum, acrosome, and nucleus of spermatids and epididymal spermatozoa. Degenerative changes in Leydig cells result in reduced testosterone production, causing regression of seminiferous tubules and structural damage to the epididymis, ultimately terminating spermatogenesis which leads to infertility. Decrease in levels of testosterone and activities of various antioxidant enzymes resulting in greater oxidative stress was also seen.

CONCLUSIONS

Fluoride has various detrimental effects on male reproductive system and overall reproductive health. This type of study is important for understanding the effects of fluoride toxicity so that health officials can guide public about safe fluoride exposure limits and the damages it can cause in higher concentrations. Studies using various natural and synthetic ameliorative substances mentioned in the text later can prove to be helpful for development of various therapeutic approaches to mitigate the effects of fluoride toxicity.

Activation of Nrf-2 Transcription Factor and Caspase Pathway with Royal Jelly Reduces Fluoride Induced Testicular Damage and Infertility in Rats

This study was carried out to investigate the protective properties of royal jelly on the testicular tissue of rats with testicular damage by giving fluoride. Sperm motility, epididymal sperm density and abnormal sperm ratios were examined and visualized with a light microscope. Expression levels of Caspase-3, Bcl-2, Nrf-2, NF-κB, COX-2, TNF-α and IL1-α proteins in testis tissue were determined by western blot technique. As a result of the study, MDA level, expression level of Bcl-2, NFҡB, COX-2, TNF-α and IL1-α proteins, abnormal sperm rates were found higher in Fluoride-50 and Fluoride100 groups compared to other groups. In addition GSH, Catalase enzyme levels, expression levels of Caspase-3 and Nrf-2 proteins were found to be higher in Fluoride + Royal Jelly groups compared to Fluoride-50 and Fluoride-100 groups. In addition, lower degeneration of testicular tissue was found in the histological evaluation in the Fluoride + Royal Jelly groups compared to the other groups. When the data are evaluated royal jelly provides effective protection against testicular damage. From this point of view, we hope that similar results will be obtained when royal jelly is tested on humans.

Vitamin C and E supplementation can ameliorate NaF mediated testicular and spermatozoal DNA damages in adult Wistar rats

OBJECTIVE

Present study was designed to explore the efficacy of vitamin C and E (VC&VE) against fluoride mediated testicular, epididymal and spermatozoal anomalies.

MATERIALS AND METHODS

Thirty two adult Wistar rats were divided into four groups. Group-I was control; Group-II received sodium fluoride (NaF) at 15 mg/kg/day dose; Group-III was provided with VC (200 mg/kg/day) and VE (400 mg/kg/day) plus NaF; Group-IV received only VC&VE. Structural integrity and oxidative stress markers (superoxide dismutase, catalase, malondialdehyde and protein carbonyl) of testis and epididymis were assessed. Spermatozoal parameters (count, motility, viability and hypo-osmotic swelling) were evaluated. Testicular functional maker enzymes (acid phosphatase, alkaline phosphatase and lactate dehydrogenase) were also assessed. Integrity of testicular and spermatozoal DNA were evaluated. Testicular fluoride content was measured.

RESULT

Fluoride induced structural changes and alterations of oxidative stress markers were observed in testis and epididymis. Spermatozoal potentials were altered and reduced activities of testicular functional marker enzymes were observed. Fluoride caused testicular and spermatozoal DNA damages. VC&VE supplementation resulted in protectionfrom all fluoride mediated alterations and helped in attenuating testicular fluoride accumulation.

CONCLUSION

Antioxidant properties of VC&VE ameliorated fluoride mediated reproductive damages but only supplementation did not exhibit any notable effect compared to control rats.

Dietary Calcium Alleviates Fluorine-Induced Liver Injury in Rats by Mitochondrial Apoptosis Pathway

Excessive fluoride (F) exposure can lead to liver damage; moreover, recent studies found that the addition of appropriate calcium (Ca) can alleviate the symptom of skeletal fluorosis. However, whether Ca can relieve F-induced liver damage through the mitochondrial apoptosis pathway has not been reported yet. Therefore, we assessed the liver morphology, serum transaminase content, liver oxidative stress-related enzymes, and apoptosis-related gene and protein expression in Sprague Dawley (SD) rats treated with 150 mg/L sodium fluoride (NaF) and different concentrations of calcium carbonate (CaCO₃) for 120 days. Our results showed that NaF brought out pathological changes in liver morphology, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels increased, total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) content decreased, and malondialdehyde (MDA) content increased, suggesting that NaF caused hepatotoxicity and oxidative stress. In addition, the results of quantitative real-time PCR (qRT-PCR) and immunohistochemistry showed that NaF exposure upregulated the expression of Bcl-2-associated x protein (Bax), rho-related coiled-coil kinase 1 (ROCK1), cytochrome C (Cyto-C) mRNA and protein (P < 0.01), and downregulated B cell lymphoma 2 (Bcl-2) protein and mRNA (P < 0.01), indicating that excessive F exposure activated mitochondrial-mediated apoptosis in the liver. However, the addition of 1% CaCO₃ to the diet significantly increased the expression of anti-apoptotic gene Bcl-2 (P < 0.01), inhibited the activation of the mitochondrial apoptosis pathway, and reduced mitochondrial damage. In summary, supplementing 1% CaCO₃ in the diet can alleviate the NaF-induced liver cell damage through the mitochondrial apoptosis pathway.

Cnidoscolus aconitifolius leaf extract and ascorbate confer amelioration and protection against dimethyl nitrosamine-induced renal toxicity and testicular abnormalities in rats

Extracts of Cnidoscolus aconitifolius (CA) have been reported to possess medicinal properties ranging from potential hepatoprotective, anti-diabetic, and anti-cardiovascular. In our previous study, gas chromatography mass spectroscopy check of CA extract showed the inclusion of 2,4-bis(1,1-dimethylethyl)-phenol, a phenolic phyto-compound that constitutes about 45 %, carotene and linoleic acid sources, and silicon-rich components. Hence we compare the preventive and ameliorative potentials of CA with ascorbate in dimethyl nitrosamine (DMN)-induced renal toxicity and sperm abnormalities in rats. Renal toxicity was investigated by quantifying the levels and activities of endogenous antioxidant parameters. Renal damage marked by significant reduction in GSH level, as well as significant elevation in MDA concentration, and activities of GPx, GST, CAT, and SOD were restored after the intervention of CA and ascorbate. Also, there was decrease in live sperm, sperm concentration, sperm gross and individual motility, and normal sperm morphology, following DMN administration. Based on the gathered results, it is concluded that ascorbate and CA demonstrate comparable ameliorative and protective effects against DMN-induced renal and testicular toxicities in rats.

Fluoride induced testicular toxicities in adult Wistar rats

Fluoride is essential for the development of teeth and bone but its excessive exposure causes reprotoxic effects. We have studied the graded effects of different doses of sodium fluoride (NaF) on 24 adult Wistar rats which were randomly divided into four groups (n = 6). All the rats were given normal diet prepared in our laboratory. Control (group I) rats were received vehicle only and treated rats (group II, III, and IV) were administered NaF orally at 10, 15, and 20 mg/kg/d doses, respectively, for 30 consecutive days. Gravimetric index of testis was decreased significantly in group III and IV rats but such changes were not observed in the accessory reproductive organs. Marked alterations in number, motility, viability, and plasma membrane functional integrity of caudal spermatozoa were noted in most of the treated groups. Noticeable alterations in testicular histoarchitecture were observed in group III and IV rats. Graded Changes of testicular redox homeostasis were noted by assessment of enzymatic (superoxide dismutase [SOD], catalase, glutathione s-transferase [GST], and glutathione peroxidase [GPx]) and nonenzymatic (malondialdehyde [MDA] and protein carbonyl [PC]) markers. Changes of testicular functional markers (acid phosphatase [ACP], alkaline phosphatase [ALP], and lactate dehydrogenase (LDH) activity) were noted in group III and IV rats. DNA fragmentation assay proved the possibility of DNA damage caused by oxidative stress, as evidenced by prominent trailing pattern of fragmented testicular genomic DNA from group III and IV rats. The study concludes that fluoride-mediated oxidative stress not only impedes the structural and functional facets of testis but also results in testicular DNA damage.

Effects of the methanol root extract of Carpolobia lutea on sperm indices, acrosome reaction, and sperm DNA integrity in cadmium-induced reproductive toxicity in male Wistar rats

OBJECTIVE

Oxidative stress is a mechanism of cadmium-induced reproductive dysfunction. Carpolobia lutea is a free radical scavenger. Our study investigated the potential protective effects of Carpolobia lutea root methanol extract against cadmium-induced reproductive toxicity.

METHODS

We obtained the Carpolobia lutea root in Akure, and it was authenticated at the Forestry Research Institute of Nigeria (FRIN) herbarium, Ibadan, Nigeria, with FHI number 109784. We used Soxhlet extraction to obtain its methanol extract. We used thirty male Wistar rats (150-170g) in this study, (n=5 per group), and treated them as follows: Control (1 ml/kg normal saline), Cd (2 mg/kg), Cd+MCL (2 mg/kg+100 mg/kg), Cd+MCL (2 mg/kg+200 mg/kg), MCL (100 mg/kg), MCL (200 mg/kg). We administered Carpolobia lutea orally for 8 weeks. We administered a single dose of 2 mg/kg of cadmium intraperitoneally. We assessed the sperm profile using a computer-aided sperm analyzer. Under microscopy, we determined the sperm acrosome reaction and the DNA damage. We measured the seminal fructose level using spectrophotometry, and the data were analyzed using ANOVA at p<0.05.

RESULTS

Cd+MCL (2mg/kg+200 mg/kg) significantly increased sperm count (339.0±25.0 vs. 29.0±4.5 million/mL), motility (80.0±0.2 vs. 55.0±4.9%), viability (68.7±2.7 vs. 31.3±2.9%) and decreased abnormal sperm (28.3±1.7 vs. 43.3±2.5%), relative to the cadmium group. Cd+MCL (2mg/kg+200 mg/kg) significantly increased acrosome reaction (68.0±7.5 vs. 15.2±2.4%) and seminal fructose level (0.49±0.06 vs. 0.28±0.06 mmol/L) relative to the cadmium group. Cd+MCL (2mg/kg+200 mg/kg) significantly decreased sperm DNA damage (14.1±1.6 vs. 35.9±5.3%) in relation to the cadmium group.

CONCLUSIONS

Carpolobia lutea root extract improves the sperm variables of rats exposed to cadmium.

Fluoride-induced testicular degeneration and sperm quality deteriorations: Salutary role of Cyperus esculentus tubers (tiger nut) extract in animal model

OBJECTIVE

Chronic exposure to fluoride causes tissue damage induced by oxidative imbalance, Cyperus esculentus (CE) possess anti-inflammatory and immunostimulatory properties. This study focused on Salutary role of Cyperus esculentus in sodium fluoride (NaF) induced testicular degeneration and sperm quality deteriorations.

METHODS

Sexually mature male Sprague-Dawley rats were randomly divided into four groups (n=6). Animals in control group received 2 mls of normal saline per day; CE group received 500mg/kg bw of CE; NaF group received 5mg/kg bw of NaF; NaF+CE group received 500mg/kg bw of CE (for 14 days pre-treatment) and NaF co-treatment till 56 days via gastric gavage. Parameters tested include: testicular histology, sperm parameters, sex hormone, fertility test, malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione, glutathione peroxidase (GPX), catalase (CAT), testicular fluoride and testicular cholesterol.

RESULTS

Sodium fluoride significantly (p<.05) decrease testicular antioxidant (SOD, CAT, GSH and GPx), sperm quality, hormone profiles (TT, FSH, LH, estrogen levels), testicular cholesterol, morphometric parameters, Johnsen's Score and number of implantations in female rats with corresponding (p<.05) increase in oxidative stress makers and abnormal sperm morphology. Also depleted seminiferous epithelium and degenerate spermatogenic cells. Pretreatment with 500mg/kg bw of CE lowered NaF toxicity by significantly reducing the lipid peroxidation products, fluoride accumulation in the testis, histopathological changes of the testes and spermatozoa abnormalities and reverted observed NaF-induced inhibition in antioxidant parameters and weight of accessory sex organs.

CONCLUSIONS

Cyperus esculentus attenuated NaF-induced testicular injuries and protected the seminiferous epithelium, reduced oxidative stress and promoted spermatogenesis.

Sodium fluoride disrupts testosterone biosynthesis by affecting the steroidogenic pathway in TM3 Leydig cells

Fluorine is an essential trace element to which humans and animals are exposed through water, food, air and products used for dental health. Numerous studies have reported the detrimental effects of fluoride on testicular function and fertility; however, the underlying mechanisms of testosterone biosynthesis remain unclear. In this study, Leydig cells, the primary cells responsible for the production and regulation of steroid hormones in the testis, were used to elicit effects of sodium fluoride on the steroidogenic pathway. Leydig cells were treated with 0, 0.1, 1, 10 and 100 mg/L sodium fluoride for 24 h, respectively. The result of the study showed that sodium fluoride significantly decreased cell viability and cell proliferation, increased cell cytotoxicity and decreased the amounts of testosterone and 3',5'-cyclic adenosine monophosphate levels in a concentration-dependent manner. Also, these results indicated that NaF suppressed the expression of steroidogenic genes (steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, 3β-hydroxy dehydrogenase type I and 17β-hydroxy dehydrogenase type III) and proteins (luteinizing hormone receptor, cholesterol side-chain cleavage enzyme, 3β-hydroxy dehydrogenase), by changing the mRNA expression levels of the transcription factors (steroidogenic factor-1, GATA binding protein-4, nerve growth factor IB and nuclear receptor subfamily 0 group B member 1).

Vitamin E and lycopene reduce coal burning fluorosis-induced spermatogenic cell apoptosis via oxidative stress-mediated JNK and ERK signaling pathways

Although fluoride has been widely used in toothpaste, mouthwash, and drinking water to prevent dental caries, the excessive intake of fluoride can cause fluorosis which is associated with dental, skeletal, and soft tissue fluorosis. Recent evidences have drawn the attention to its adverse effects on male reproductive system that include spermatogenesis defect, sperm count loss, and sperm maturation impairment. Fluoride induces oxidative stress through the activation of mitogen activated protein kinase (MAPK) cascade which can lead to cell apoptosis. Vitamin E (VE) and lycopene are two common antioxidants, being protective to reactive oxygen species (ROS)-induced toxic effects. However, whether and how these two antioxidants prevent fluoride-induced spermatogenic cell apoptosis are largely unknown. In the present study, a male rat model for coal burning fluorosis was established and the histological lesions and spermatogenic cell apoptosis in rat testes were observed. The decreased expression of clusterin, a heterodimeric glycoprotein reported to regulate spermatogenic cell apoptosis, was detected in fluoride-treated rat testes. Interestingly, the co-administration with VE or lycopene reduced fluorosis-mediated testicular toxicity and rescued clusterin expression. Further, fluoride caused the enhanced Jun N-terminal kinase (JNK, c-Jun) and extracellular signal-regulated protein kinase (ERK) phosphorylation, which was reduced by VE or lycopene. Thus, VE and lycopene prevent coal burning fluorosis-induced spermatogenic cell apoptosis through the suppression of oxidative stress-mediated JNK and ERK signaling pathway, which could be an alternative therapeutic strategy for the treatment of fluorosis.

Histopathological findings of renal tissue induced by oxidative stress due to different concentrations of fluoride

It has been reported that excessive intake of fluoride can induce renal lesions. However, its pathogenesis is still less understood. Therefore, this study was conducted to investigate oxidative damage and the relationships between the oxidative damage and renal lesions in fluoride-treated mice by using the methods of histopathology, biochemistry, flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR). A total of 240 ICR mice were randomly divided into four equal groups (sodium fluoride was given orally at the dose of 0, 12, 24 and 48 mg/kg body weight for 42 days, respectively). We found that fluoride in excess of 12 mg/kg induced renal oxidative damage, which was characterized by increasing the levels of reactive oxygen species (ROS) production and contents of malondialdehyde (MDA) and protein carbonyls (PC), and decreasing the abilities of anti-superoxide anion (ASA) and anti-hydroxyl radical (AHR), glutathione (GSH) content, as well as activities and mRNA expression levels of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-Px). Concurrently, fluoride caused degeneration and necrosis of the tubular cells, renal tubular hyaline casts and glomeruli swelling, which were consistent with the alteration of renal function parameters including elevated contents of serum creatinine (Cr), serum uric acid (UA), blood urea nitrogen (BUN), and the activities of urinary N-acetyl-b-D-glucosaminidase (NAG), renal lactate dehydrogenase (LDH), and reduced activities of sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and acid phosphatase (ACP) in the kidney. The above-mentioned results showed that fluoride in excess of 12 mg/kg induced renal oxidative damage, which then caused renal lesions and dysfunctions. These findings also clearly demonstrated that oxidative damage is one of the mechanisms of fluoride-induced renal lesions and dysfunctions.

Dietary High Fluorine Alters Intestinal Microbiota in Broiler Chickens

This study investigated the effects of dietary high fluorine on ileal and cecal microbiota in broiler chickens. Two hundred eighty 1-day-old broiler chickens were randomly assigned to four groups and raised for 42 days. The control group was fed a corn-soybean basal diet (fluorine 22.6 mg/kg). The other three groups were fed the same basal diet, but supplemented with 400, 800, and 1200 mg/kg fluorine (high fluorine groups I, II, and III), administered in the form of sodium fluoride. The microbiota of ileal and cecal digesta was assessed with plate counts and polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE). It was found that, compared with those in the control group, the counts of Lactobacillus spp. and Bifidobacterium spp. were markedly decreased (P < 0.01 or P < 0.05), whereas the counts of Escherichia coli and Enterococcus spp. were significantly increased (P < 0.01 or P < 0.05) in the high fluorine groups II and III. PCR-DGGE analysis showed that the number of DGGE bands, similarity, and Shannon index of ileal and cecal bacteria were markedly reduced in the high fluorine groups II and III from 21 to 42 days. Sequencing analysis revealed that the composition of the intestinal microbiota was altered in the high fluorine groups. In conclusion, dietary fluorine in the range of 800-1200 mg/kg obviously altered the bacterial counts, and the diversity and composition of intestinal microbiota in broiler chickens, a finding which implies that dietary high fluorine can disrupt the natural balance and structure of the intestinal microbiota.

Sodium fluoride disrupts DNA methylation of H19 and Peg3 imprinted genes during the early development of mouse embryo

Sodium fluoride (NaF) is associated with embryonic and fetal development abnormalities, but the mechanism by which this occurs is unclear. DNA methylation, an important epigenetic reprogramming mechanism, is essential for normal embryonic development. Thus, we investigated the effect of NaF on DNA methylation in early mouse embryos, as well as mouse sperm and liver using bisulfite sequencing and ELISA. Data indicate that H19, a paternally imprinted gene, compared to control embryos, was less methylated in 8-cell embryos from pregnant mice treated with NaF (100 mg/l) in drinking water for 48 h. Peg3, a maternally imprinted gene, and the Line1 repeated sequence were similarly methylated in NaF-treated and control embryos. Oral ingestion of NaF for 35 days did not significantly change Line1 and genomic global DNA methylation in the liver. H19, Rasgrf1, Line1, and genomic global DNA methylation were also similar in NaF-treated and control sperm. Female mice mated with NaF-treated male mice (35 days) had less methylated H19, but Peg3 was significantly more methylated. Line1 was similarly methylated in treated 8-cell embryos, compared to control embryos. NaF treatment of male mice before copulation significantly increased the expression of H19 in blastocysts, whereas H19 expression was not detected in 8-cell embryos. Data suggest that NaF may interact directly with the embryo to disrupt the maintenance of normal gene imprinting during pregnancy. Long-term NaF exposure of males may not directly affect DNA methylation of the sperm and liver, but the sperm may signal to early embryos with abnormal gene imprinting.

Proteomic analysis of urine in rats chronically exposed to fluoride

Urine is an ideal source of materials to search for potential disease-related biomarkers as it is produced by the affected tissues and can be easily obtained by noninvasive methods. 2-DE-based proteomic approach was used to better understand the molecular mechanisms of injury induced by fluoride (F(-)) and define potential biomarkers of dental fluorosis. Three groups of weanling male Wistar rats were treated with drinking water containing 0 (control), 5, or 50 ppm F(-) for 60 days (n = 15/group). During the experimental period, the animals were kept individually in metabolic cages, to analyze the water and food consumption, as well as fecal and urinary F(-) excretion. Urinary proteome profiles were examined using 2-DE and Colloidal Coomassie Brilliant Blue staining. A dose-response regarding F(-) intake and excretion was detected. Quantitative intensity analysis revealed 8, 11, and 8 significantly altered proteins between control vs. 5 ppm F(-), control vs. 50 ppm F(-) and 5 ppm F(-) vs. 50 ppm F(-) groups, respectively. Two proteins regulated by androgens (androgen-regulated 20-KDa protein and α-2μ-globulin) and one related to detoxification (aflatoxin-B1-aldehyde-reductase) were identified by MALDI-TOF-TOF MS/MS. Thus, proteomic analysis can help to better understand the mechanisms underlying F(-) toxicity, even in low doses.

Effects of sodium fluoride exposure on some biochemical parameters in mice: evaluation of the ameliorative effect of royal jelly applications on these parameters

Forty eight male Balb/c mice, each weighing 30-35 g, were used in the present study. The animals were divided into four equal groups. The first group served as the control group, and the second group was administered royal jelly at a dose of 50 mg/kg bw by gavage for a period of 7 days. The third group received 200 ppm fluoride, as sodium fluoride, for a period of 7 days, in drinking water. Lastly, the fourth group was given 200 ppm fluoride in drinking water, in association with royal jelly at a dose of 50 mg/kg bw by gavage, for a period of 7 days. At the end of the seventh day, blood samples were collected from all groups into heparinised and dry tubes, and liver samples were taken concurrently. Erythrocyte and liver tissue malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were evaluated in the blood and tissue samples obtained. Furthermore, serum cholesterol, triglyceride, glucose, total protein and albumin levels, and aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alcaline phosphatase (ALP) activities were evaluated. In conclusion, fluoride was determined to cause adverse effects in mice, and the administration of royal jelly to these animals alleviated the adverse effects of fluoride.

Effect of long-term fluoride exposure on lipid peroxidation and histology of testes in first- and second-generation rats

This experiment was designed to investigate the histological and lipid peroxidation effects of chronic fluorosis on testes tissues of first- and second-generation rats. Sixteen virgin female Wistar rats were mated with eight males (2:1) for approximately 12 h to obtain first-generation rats. Pregnant rats were divided into two groups: controls and fluoride-given group, each of which containing five rats. Pregnant rats in the fluoride-given group were exposed to a total dose of 30 mg/l sodium fluoride (NaF) in commercial drinking water containing 0.07 mg/l of NaF throughout the gestation and lactation periods. After the lactation period, the young animals (first generation, F1) were exposed to the same dose of NaF in drinking water for 4 months. At the end of the 4 months of experimental period, nine randomly chosen male rats (F1) were killed and testes tissues were taken for histopathological and biochemical analysis. The remaining eight female rats were mated with four males (2:1) for approximately 12 h to obtain second-generation rats. Six female were identified as pregnant and treated with similarly throughout the gestation and the lactation periods. After the lactation period, the young male animals (second generation, F2) were also treated in the same way for 4 months. At the end of the 4 months of experimental period, nine randomly chosen male rats (F2) were killed and testes tissues were collected for histopathological and biochemical analysis. The rats in the control group were applied the same procedure without NaF administration. In biochemical analysis of the fluoride given F1 and F2 rats, it has been found that plasma fluoride levels and testes thiobarbituric acid reactive substance levels were significantly increased when compared with the control group. In F1 and F2 rats, similar histopathological changes were observed. In both groups, spermatogenesis was severely reduced. Spermatogonia and primary spermatocytes were normal, however, there was a widespread degeneration in other spermatogenic cell lines of the seminiferous epithelium. The histological structures of the Sertoli and interstitial Leydig cells were normally observed. It is concluded that chronic fluorosis exposure leads to a remarkable destruction in testes tissues of F1 and F2 rats via lipid peroxidation.