The Effect of Vitamin C on the Reproductive Functions of Paraquat Intoxicated Male Albino Rats (Rattus norvegicus)

Abstract

Paraquat (PQ) is a bipyridylium herbicide applied around trees in Orchids and between crop rows to control broad-leaved and grassy weeds. Its oxidation results in the formation of superoxides and supernitrite species which causes damage to cellular components. Studies have implicated PQ as one of the pesticides that contributes to the reduction in male reproductive functions in humans and animals during exposure. This study, therefore, determined the antioxidant effect vitamin C has on the reproductive functions of PQ insulted rats. Ninety-six (96) male albino rats, grouped twelve (12) rats per subgroup were intraperitoneally injected with different sublethal increasing doses of PQ, respectively on biweekly (14 days) intervals over a period of three months (84 days). Subsequently, the subgrouped animals (Avc, Bvc, Cvc and Dvc) were maintained orally with 1 g/L (1000 mg/L) vitamin C, while the other subgrouped animals (A, B, C and D) were maintained orally with drinking water with negligible vitamin C content throughout the study period. At the end of each monthly (28 days) treatment, four animals per subgroup were selected, anaesthetized with gaseous Isoflurane and 5 mls of blood samples collected using Cardiac puncture procedure. The animals were later decapitated and their testis harvested, with the semen samples collected from the tail of the epididymis through an incision made with a scalpel blade. The samples collected were analyzed for blood – LH, FSH and Testosterone (Te), Semen analysis and the histopathology testicular tissues. The dose and exposure-time dependent PQ toxicity induced testicular degeneration with seminiferous tubular damage, disruption of spermatogenesis, increased incidences of dead and abnormal sperm cells, decline in sperm concentration and sperm motility. These effects were enumerated thus: a significant decline in the %Counts of progressive motile cells, %Counts of Life cells, %Counts of Normal cells and the total sperm cell counts; with a significant elevations in the %Counts of Non-motile cells, %Counts of Abnormal and Dead cells. The hormones LH, FSH and Te analyzed showed no significant change as a result of PQ exposure. Treatments of test animals with vitamin C medication resulted in the significant improvements on the %Counts of Progressive motile sperm cells, the %Counts of Life cells, the %Counts of Normal cells and the total sperm cell concentration counts. Vitamin C treatments also reduced the degree of testicular degeneration, improved on spermatogenesis with near-normalization of seminiferous interstitial connective tissues and Sertoli cells density. Vitamin C medication did not have any effect on the sex hormone assayed. These findings clearly supports the general statement that vitamin C has an important role to play in the normalization of occupationally or environmentally induced male infertility as a result of Paraquat exposure to Animals and Man. 

Keywords: Paraquat, vitamin C, reproductive function, spermatozoa, parametric