Toksikokinetika bisfenola A pri ovcah in njegov vpliv na spolne organe ovnov v puberteti

Šturm, Sabina (author), Cerkvenik Flajs, Vesna (mentor), Švara, Tanja (comentor)

Namen prvega sklopa doktorske naloge je bil preučiti toksikokinetične (TK) parametre pri ovci in ovnih pasme istrska pramenka po zaporednem dietarnem in podkožnem vnosu bisfenola A (BPA). Za določanje koncentracije prostega in celokupnega BPA v krvni plazmi, mleku, urinu in iztrebkih ovce ter za določanje koncentracije celokupnega BPA v krvni plazmi ovnov smo razvili in validirali tekočinsko kromatografijo visoke ločljivosti na obrnjeni stacionarni fazi ter s fluorescenčno detekcijo. V prvi, pilotni raziskavi, opravljeni na eni ovci v laktaciji s sesnim jagnjetom, smo na podlagi meritev koncentracije prostega in celokupnega BPA v krvni plazmi z neprostorsko TK analizo izračunali osnovne TK parametre po dietarnem in podkožnem vnosu v odmerku 100 µg/kg t. m./dan in ugotovili, da je način vnosa vplival na TK parametre prostega BPA pri ovci. Po dietarnem vnosu je bila izpostavljenost ovce prostemu BPA manjša in krajša – površina pod koncentracijsko krivuljo v krvni plazmi (AUC) je bila 1,28?µg?h/l v primerjavi s podkožnim vnosom, pri katerem je bila AUC prostega BPA 33,3?µg?h/l. TK profila celokupnega BPA pa sta si bila zelo podobna. Z razvojem prostorskega TK modela smo ocenili, da se je v mleko izločilo manj kot 0,1 % odmerka, ki ga je prejela ovca, ne glede na način vnosa. V urinu ovce smo izmerili zelo nizke vrednosti prostega BPA in visoke vrednosti celokupnega BPA. V iztrebkih ovce smo izmerili zelo nizke vrednosti prostega in celokupnega BPA. Po štirikrat manjšem odmerku, ki so ga prejeli ovni, smo v krvni plazmi določili tudi približno štirikrat manjšo najvišjo koncentracijo (Cmax) celokupnega BPA. Namen drugega sklopa doktorske naloge je bil preučiti vpliv dvomesečne dietarne izpostavljenosti v odmerku BPA 25 µg/kg t. m./dan na spolne organe ovnov v puberteti. Med tretirano skupino in kontrolno skupino ovnov nismo ugotovili statistično značilnih razlik v telesni masi, masi mod, pogostosti ali jakosti histopatoloških sprememb v modih in nadmodkih, v kvalitativnih lastnostih semenčic ter koncentraciji semenčic v nadmodkih in semenovodih. Prav tako nismo ugotovili statistično značilnih razlik v premeru in površini zvitih semenskih kanalčkov. Statistično značilno razliko smo ugotovili le pri višini zarodnega epitela zvitih semenskih cevk, ki je bila nižja pri tretiranih ovnih.

• Language: Slovenian
• Keywords: fenoli – analize, toksikokinetika, kromatografija, tekočinska, kemijske analize krvi, mleko – analize, urin – analize, feces – analize, reprodukcija, modo, nadmodek, ovce
• Work type: Doctoral dissertation
• Organization: VF - Veterinary Faculty
• Year: 2022
• PID: 20.500.12556/RUL-141671
• Publication date in RUL: 05.10.2022

Secondary language

• Language: English
• Title: Toxicokinetics of bisphenol A in sheep and its effects on reproductive organs of rams in puberty

Abstract

The aim of the first part of the doctoral dissertation was to study toxicokinetic (TK) parameters in a ewe and rams of the Istrian pramenka sheep breed after sequential dietary and/or subcutaneous administration of bisphenol A (BPA). A chemical analysis using high performance liquid chromatography with reversed stationary phase and fluorescence detection was developed and validated for the determination of free and total BPA in sheep’s blood plasma, milk, urine and feces. In an initial pilot study conducted on a lactating ewe with a suckling lamb, a non-compartmental TK analysis was performed for both the dietary and the subcutaneous route. In each case, 100 µg BPA/kg body weight/day was administered, and the free and total BPA in the blood plasma was determined. It was found that the administration route affected the TK parameters of free BPA. After dietary administration, the ewe’s exposure to free BPA was lower and shorter - the area under the blood plasma concentration curve (AUC) was 1.28 µg h/l, compared to subcutaneous administration, where the AUC of free BPA was 33.3 µg h/l. However, the TK profiles of total BPA were very similar. Moreover, with the development of the TK compartmental model, we estimated that the percentage of BPA excreted in milk was less than 0.1% of the received dose, regardless of the route of administration. In the urine of the ewe we also determined very low levels of free BPA and high levels of total BPA, while very low levels of both free and total BPA were also determined in the feces. After a fourfold reduction of the dose, which was administered to the rams, an approximately fourfold reduction of the maximum plasma concentration (Cmax) of total BPA in their blood plasma was also observed. The second part of the dissertation aimed to investigate the effect of a two-month dietary exposure of BPA to 25 µg/kg of body weight/day on the male reproductive organs of pubescent rams. We found no statistically significant difference between the treatment and control group of rams regarding body weight, testicular weight, frequency or severity of histopathological changes in the testes and epididymis, qualitative characteristics of spermatozoa, concentration of spermatozoa in the epididymis and in the ductus deferens. We also found no statistically significant difference in the diameter and surface area of the seminiferous tubules. The only statistically significant difference was a lower height of the germinal epithelium of the seminiferous tubules in the treated rams compared to the control rams.

• Keywords: phenols – analysis, toxicokinetics, chromatography, high pressure liquid, blood chemical analysis, milk – analysis, urine – analysis, feces – analysis, reproduction, testis, epididymis, sheep