Citation:Deepananda, K.H.M.A., De Silva, W.A.J.P., Chandana, E.P.S., Priyanka, S.B.T., Weerasinghe, S.S.S., Pitadeniya, G.S., Peiris, L.D.C., Samayawardhena, L.A., & Dharmasiri, H.W. (2000). Chronic Exposure to Paraquat Alters Spermatogenesis and Nuclear DNA Integrity of Epididymal Sperm in Mice. Proceedings of the Twentieth Annual Sessions of the Institute of Biology, 27.
Date:2000
Abstract:
Experimental evidence suggests that unintentional exposure to environmental chemicals may
alter reproductive capability of males. The aim of the present study was to investigate effects of low concentrations of Paraquat (1,1'-dimethyl l-4,4'-brpyridinium), a commonly usecl
broad-spectntm weedicide in Sri Lanka, on spermatogenesis of mice. Sexually mature mice
were treated with 4 doses (7
, z, 4 and g mg &g body weight) of paraquat (n= I 0 / group) and
the vehicle (distilled water: n = l0). Each dosage (in 0. t mt; was injected into the scrotal sac
every other day for 7 days. Testicular spemn count and histological studies fdiameter of
seminiferous tubule (width), thickness of the tubules, number of cyclesl were determined on
post treatment day 7. Nuclear integrity of sperm DNA and abnormalities in sperm morphol ogy (using separate sperm smears) were determined. Treated mice showed a significant
(p<0'05) increase in sperm abnormalities (for 1,2 and 4 mg/kgdoses) and nuclear integrity
of sperm DNA in caput, corpus and cauda sperm of the epididymis. Results revealed disrup- tion of spermatogenesis process in all treated groups. Sp"r.n abnormalities were mainly
concentrated on the sperm head. In addition, a significant (p<0.05) increase in tubular diam eter and a significant (p<0.05) reduction in Sertoli cell number and in round and elongatecl
spermatids were observed in all treated groups. Earlier stlldies have shown that Ethylene
GlycolMonomethyl Ether and its by products cause severe damages in the spermatogenesis
in rat' This study suggests whether effects of Paraquat are mediated through Jamaged Sertoli
cells' But a conclusion cannot be drawn from the present findings alone. HoweveE it is
possible that tiee radical forrnation can interfere with integrity of Sertoli cells and sperrna togenesis. Further experiments are needed to conclude the mechanism of action of paraquart
on epididymal sperm DNA.
