Effects of alfa-cypermethrine and imidacloprid on oxidative stress parameters in testes and epididymis of Wistar rats

U današnje vrijeme raste potrošnja novih vrsta insekticida, razvijenih kao zamjena konvencionalnim organofosfatnim insekticidima, kao što su piretroidi ili "zeleni" insekticidi poput α-cipermetrina i neonikotinoidne tvari poput imidakloprida. Dostupni podaci o njihovom utjecaju na reprodukcijski sustav su oskudni ili preliminarni, a toksičnost niskih koncentracija navedenih insekticida do danas nije detaljno proučena. U ovom je istraživanju ispitan utjecaj α-cipermetrina i imidakloprida na parametre oksidacijskog stresa primjenom pristupa s više biomarkera na uzorcima tkiva testisa i epididimisa odraslih štakora soja Wistar. Životinje su oralnim putem uzastopno tijekom 28 dana tretirane koncentracijskim razinama insekticida koje se mogu susresti u svakodnevnom životu, izračunatim na temelju nekoliko toksikološki referentnih vrijednosti (0,02 (ADI); 0,15 (OEL); 0,80 (5×OEL); 2,20 (REL) mg α-cipermetrina/kg t.m./dan i 0,06 (ADI); 0,80 (10×AOEL); 2,25 (1/200 LD50) mg imidakloprida/kg t.m./dan). Oba su insekticida uzrokovala značajno smanjenje prirasta mase tretiranih životinja u odnosu na kontrolnu skupinu, ali je manji prosječan prirast mase uočen kod životinja tretiranih α-cipermetrinom u odnosu na one tretirane imidaklopridom. Životinje tretirane najvišom dozom imidakloprida imale su značajno manju masu testisa u odnosu na kontrolnu skupinu životinja dok tretman α-cipermetrinom nije utjecao na promjenu mase testisa i epididimisa. Značajan porast aktivnosti enzima glutation peroksidaze (GPx) u testisu uzrokovao je α-cipermetrin pri najvišoj primijenjenoj dozi. Tretman α-cipermetrinom ili imidaklopridom rezultirao je značajanim porastom koncentracije glutationa (GSH) i aktivnosti antioksidacijskih enzima GPx-a i bakar, cink-ovisne superoksid dismutaze (CuZnSOD) u epididimisu. Tretman α-cipermetrinom uzrokovao je veći porast koncentracije GSH u tretiranih životinja u usporedbi s imidaklopridom, ali je porast aktivnosti GPx-a bio znatno manji nego kod tretmana imidaklopridom. Aktivnost CuZnSOD-a imala je sličan porast u odnosu na kontrolnu skupinu kod oba tretmana.The use of pyrethroids such as α-cypermethrine, and neonicotinoid insecticides like imidacloprid has been increasing during the past decade accompanied by the decline in use of organophosphate pesticides. There are several reports indicating adverse health effects of α-cypermethrine and imidacloprid. However, data on their effect on the reproductive system are scarce or preliminary, and the toxicity of low concentrations of these insecticides has not been studied to date. The effects of α-cypermethrine and imidacloprid exposure on oxidative stress biomarkers in testes and epididymis were studied in adult male Wistar rats treated with doses comparable to currently proposed health-based reference values. Rats were orally administered with α-cypermethrine (0,02 (ADI); 0,15 (OEL); 0,80 (5×OEL); 2,20 (REL) mg/kg b.w./day) or imidacloprid (0,06 (ADI); 0,80 (10×AOEL); 2,25 (1/200 LD50) mg/kg b.w./day) for 28 consecutive days. The results revealed that exposure to α-cypermethrine or imidacloprid significantly decreased body weight gain in treated groups compared to the control group. However, the average decrease was lesser in animals treated with α-cypermethrine, in comparison with those treated with imidacloprid. The weight of testes was significantly lower in animals treated with the highest dose of imidacloprid compared to controls, while treatment with α-cypermethrine had no effect on testicular/epididymal weight. Present results revealed that treatment with α-cypermethrine resulted in a statistically significant increase of glutathione peroxidase (GPx) activity in testes at the highest applied dose. Treatment with α-cypermethrine or imidacloprid resulted in a significant increase in the level of reduced glutathione (GSH) in epididymis and in the activities of epididymal GPx and Cu, Zn superoxide dismutase (CuZnSOD). When compared to the treatment with imidacloprid, treatment with αcypermethrine caused a greater increase of the GSH concentration in treated animals. Nevertheless, the increase of the GPx activity was lesser in the treatment with α-cypermethrine, than in the treatment with imidacloprid. The CuZnSOD activity had a similar increase in comparison with the control group in both treatments