An Organophosphate Insecticide Methyl Parathion (O- O- Dimethyl O-4-Nitrophenyl Phosphorothioate) Induces Cytotoxic Damage and Tubular Atrophy in the Testis Despite Elevated Testosterone Level in the Rat

Abstract

-Methyl parathion (MP) is an organophosphate pesticide used in agriculture, although quite often illegally used indoors to contain insects. The present study was planned to investigate the effects of MP on rat testis. Adult male Wistar rats (13-14 weeks) were treated with MP as follows. Experiment 1-0, 1.75, 3.5 or 7 mg/kg i.p. for 5 days and sacrificed on Day 14; experiment 2 and 3-0, 0.5, or 1 mg/kg i.p. for 12 days, and sacrificed on Days 130 and 77, respectively; experiment 4-0, 0.75, or 1.5 mg/kg i.p. for 25 days, and sacrificed on Day 17; experiment 5-0 or 3.5 mg/kg po for 25 days, and sacrificed on Day 17, after the last exposure. MP decreased the body weight and the testis weight in experiments 4 and 5 (p<0.05-0.001) due to decreased food intake and tubular atrophy respectively. MP increased the intra-testicular testosterone level and decreased the LH level in experiments 4 and 5. The seminiferous epithelium showed sloughing of germ cells, vacuoles, focal necrosis, and formation of multinucleated giant cells, cellular degeneration (nuclear pyknosis, halo appearance and shrinkage of nuclei) and tubular atrophy, especially in experiment 4. The degree of testicular damage was higher in experiment 4>5>1>3>2 indicating more effect of prolonged i.p. treatment. Homogenization-resistant spermatid count was decreased in experiments 1, 4 and 5, and MP also decreased the tubular diameter, and epithelial height (p<0.05-0.001). Incidences of stage XIV tubules, number of meiotic figures and elongating spermatids were also decreased, whereas the incidence of tubules showing epithelial sloughing increased (p<0.05-0.001). We conclude that MP is a reproductive toxicant in male rats which causes significant testicular damage in the testis.

An aminoglycoside antibiotic gentamycin induces oxidative stress, reduces antioxidant reserve and impairs spermatogenesis in rats

“…There were no significant changes in the body weight during treatment (data not shown) or in the final body weight (Table 1) indicating that GS was unable to induce a significant effect on general health conditions of rats. Decreased testis weight at a higher dose-level was due to structural changes (Narayana et al, 2006b). Histopathological changes such as epithelial cell sloughing, atrophic changes and decrease in germ cell numbers due to cytotoxicity (vide infra) were the factors responsible for decrease in the testis weight and this relation has been very well established in various other experimental conditions (Hess et al, 1988;Hess and Nakai, 2000;Narayana et al, 2006b).…”

“…Decreased testis weight at a higher dose-level was due to structural changes (Narayana et al, 2006b). Histopathological changes such as epithelial cell sloughing, atrophic changes and decrease in germ cell numbers due to cytotoxicity (vide infra) were the factors responsible for decrease in the testis weight and this relation has been very well established in various other experimental conditions (Hess et al, 1988;Hess and Nakai, 2000;Narayana et al, 2006b). Further, decrease in DSP correlated with decrease in the testis weight indicating that the germ cell death, as previously reported (Timmermans, 1989), or cell loss from the epithelium by other means such as epithelial sloughing or tubular atrophy was the main reason for decreased testis weight.…”

Methyl-parathion decreases sperm function and fertilization capacity after targeting spermatocytes and maturing spermatozoa

“…Epidemiological studies have linked exposure to OP (including Me-Pa) with decreased semen quality, increased sperm DNA damage and hormonal imbalance (Padungtod et al, 2000;Recio et al, 2001Recio et al, , 2005Sánchez-Peña et al, 2004). In addition, Me-Pa exposure caused testicular dysfunction (Narayana, 2006), reduced sperm quality (Mathew et al, 1992;Narayana et al, 2005), and increased sperm genetic damage (Narayana et al, 2005;Piña-Guzmán et al, 2006) in laboratory animals. The assessment of sperm quality is important but it is not the sole aspect for identifying and characterizing male reproductive toxicants.…”

Hazardous effect of Agricultural occupation on male fertility in central India.

“…17,18 The present study provides sufficient evidence concerning that there is a strong relation between exposure of pesticides and male semen quality.All parameters of semen analysis showed significant difference between the exposure more than 5years and exposure less then 5 years.Some studies have shown definate reletionship with exposure of Pesticides including DDT,Organophpsphorus and mixtures of herbicides, fungicides and incsecticides and decline in sperm count, motility, morpholgy. 19,20 In the present study TFSC of the groupII is less as compare to group I.As TFSC grade the overall sperm quality objectively.…”

“…Secondarily Seminiferous tubules sloughing and atrophy were confirmed in the experimental rodent models on exposed to paraquat and methyl parathion and further Gonadal hormones level may be involved in the possible mechanism of decline in semen quality . 17,18 These result suggested that the pesticides exposure really does have an adverse effect on the various parameters of seminal fluids of the farmer who are at the greater risk of having abnormal semen parameters .Our results also suggest poor semen parameters of the farmers working in fields and dealing with pesticides and insecticides for longer duration as compared to farmers whose duration of exposure is less.…”