Influência da exposição ao benzo(a)pireno no período juvenil até a peripuberdade: repercussões imediatas em ratos machos e efeitos multigeracionais e transgeracionais na prole sob parâmetros reprodutivos

Autor(es)

Bárbara Campos Jorge

• Tipo de documento: Tese de Doutorado
• Imprenta: Botucatu. 2023-03-13.
• Instituição: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu
• Data de defesa: 2023-03-01
• Orientador: Arielle Cristina Arena

Resumo

Introduction: Benzo(a)pyrene (BaP) is a substance formed by the incomplete combustion of organic compounds and is ubiquitously spread in the environment. Moreover, it is a substance with endocrine-disrupting potential that can alter the generation that was directly exposed to the injury (F0) as well as the next generation (F1). Human exposure to BaP is given through several pathways, and using an experimental rodent model, we evaluated low dose BaP with emphasis on the reproductive system during the juvenile and peripubertal period (development critical window of hormone dependent). Thus, this study evaluated the consequences of paternal (F0 generation) exposure to BaP, from juvenile to peripuberty, in F0, F1 and F2 generations on reproductive parameters in rats. Furthermore, we aimed to contribute new findings to the paradigm of the paternal origins of health and disease (POHaD), an under-explored field highly relevant to reproductive toxicology. Materials and methods: Male Wistar rats (Postnatal Day (PND) 23) were distributed into two groups (n=16 animals/group): control group (corn oil + DMSO - vehicle) and BaP-exposed group (vehicle + 0.1 μg/kg/day BaP). Treatment occurred for 31 consecutive days, orally (gavage). On PND 54, half of the animals were killed for immediate evaluation in toxicological and reproductive parameters (n=8/group). On PND 120, the rats were mated (F0 generation - n=8/group) with untreated females to obtain the F1 generation (males and females). In the adult life of the F1 generation, males were mated with untreated females to obtain the paternal lineage F2 generation (PF2) and females of the F1 generation were mated with untreated males to obtain the maternal lineage F2 generation (MF2); in both lineages, PF2 and MF2, we evaluated key points for the evaluation of reproductive toxicology. At adulthood (PND 120) of males of the F0, F1 and F2 generations, we evaluated hormone levels, testicular steroidogenic enzymes, oxidative stress in the testis and markers of proliferation and apoptosis in the seminiferous tubules. Results: On PND 54, the animals showed a decrease in the relative weight of the kidney and liver and a decrease in leukocytes. In addition, there was a reduction in diameter, height of the seminiferous tubules and serum testosterone (sT), altering spermatogenic dynamics, as well as Leydig cell (LC) atrophy and an increase in FSH levels. All steroidogenic enzymes and transporter proteins evaluated were reduced, except for StAR protein in the testis. Expression of gstp1 and ckit were decreased. The levels of antioxidants (GSH, SOD and selk) were increased, while MDA was decreased in the testis of the BaP group. Regarding to the PF2 generation, males in the BaP group showed a decrease in anogenital distance on PND 1, as well as a reduction in fertility potential, type A sperm and CL number. The females of the BaP group of the PF2 generation showed precocious puberty, decreased lordosis score in fertility, and morphological alterations of the ovary/uterus. As for the MF2 generation, the pups showed an increase in body weight on PND 1 in both sexes. The MF2 males showed a delay in puberty, altered weight of the pups in the fertility test, reduced FSH levels and increased intratesticular testosterone (iT), in addition to decreased type A sperm, histological disturbances in the epididymis, reduced 5 α-reductase, increased testicular proliferation, and increased testicular antioxidant enzymes in the BaP group. MF2 generation females showed increased uterine thickness, decreased sexual activity and decreased progesterone. Regarding the evaluations performed in the adult life of males (PND 120) of the three generations (F0, F1 and PF2) we obtained the following results: MDA was increased in all generations of the BaP group. FSH and LH decreased in F0 and sTs and iT decreased in F0 and F2 generations. Steroidogenic enzymes and transporter proteins were not altered at F0. In the BaP group of F1, only the 17β-HSD enzyme was decreased. In the PF2 generation, all enzymes and proteins evaluated were 6 decreased except cyp17a1. In F1 and PF2, cell proliferation markers (PCNA and ckit) were decreased in the seminiferous tubules. Bax expression was increased in F1 and F2, while Bcl-2 was increased only in the F0 generation of the BaP group. Conclusions: BaP caused several reproductive changes in the F0, F1, PF2 and MF2 generation that were detrimental at different levels to the fertility of these animals. Furthermore, we reinforce the need for expansion in studies on the POHaD paradigm and paternal relevance to offspring health. (AU)

• Processo FAPESP: 19/03264-5 - Influência da exposição ao benzo(a)pireno no período juvenil até a peripuberdade: repercussões imediatas em ratos machos e efeitos multigeracionais e transgeracionais na prole sob parâmetros reprodutivos
• Beneficiário: Bárbara Campos Jorge
• Modalidade de apoio: Bolsas no Brasil - Doutorado