Banca de DEFESA: JHONATAS MATEUS DA SILVA ALVES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JHONATAS MATEUS DA SILVA ALVES
DATE: 23/02/2026
TIME: 14:00
LOCAL: Sala de Microscopia - DMFA
TITLE:

ACTION OF MELATONIN ON THE LIVER OF FEMALE RATS EXPOSED TO THE INSECTICIDE BIFENTHRIN

KEY WORDS:

Hepatotoxicity; Pyrethroids; Antioxidants; Immunohistochemistry; Biochemistry; Pesticides

PAGES: 103
BIG AREA: Ciências Biológicas
AREA: Morfologia
SUBÁREA: Histologia
SUMMARY:

Pyrethroids stand out as leading agrochemicals, being widely applied in agriculture as well as in domestic insecticidal and sanitizing products. Among these compounds, bifenthrin has gained increasing dissemination and market share and has been associated with potential toxic effects on non-target organisms, particularly the liver, the main organ responsible for xenobiotic biotransformation. Given the risks associated with prolonged exposure, antioxidant strategies have proven relevant in mitigating such damage. Melatonin, with its well-established hepatoprotective activity, emerges as a promising alternative. In this context, the present study aimed to evaluate the hepatic toxic effects of bifenthrin and to investigate the potential protective effect of melatonin in an experimental model using female rats. Thirty female Wistar rats, 60 days old, were allocated into the following experimental groups: Control; BIF 3 mg/kg; BIF 6 mg/kg; BIF 3 mg/kg + MEL 10 mg/kg; and BIF 6 mg/kg + MEL 10 mg/kg. Bifenthrin was administered by gavage and melatonin intraperitoneally, both for 25 consecutive days. At the end of the experimental period, histopathological, histochemical, morphometric, immunohistochemical, and biochemical analyses of hepatic injury markers were performed, along with assessment of the organosomatic index. Statistical analysis of the data revealed that exposure to bifenthrin induced hepatic histopathological alterations, including hepatocellular ballooning, congestion of centrilobular veins, microvesicular steatosis, lobular inflammation, leukocyte infiltration, and disorganization of hepatocyte cords surrounding the centrilobular veins, with greater severity at the 6 mg/kg dose. Morphometric analysis indicated an increase in lobular parenchyma and a reduction in non-lobular parenchyma in the exposed groups, an effect attenuated by melatonin. Histochemical analysis revealed increased collagen deposition and a mild reduction in glycogen content in the livers of bifenthrin-exposed animals, accompanied by a reduction in the hepatic organosomatic index in the BIF 3 mg/kg and BIF 6 mg/kg groups. Biochemical analyses demonstrated a significant increase in serum levels of LDL, cholesterol, alkaline phosphatase, ALT, and AST, along with a reduction in HDL in these groups. Concomitant treatment with melatonin in the BIF 3 mg/kg + MEL 10 mg/kg and BIF 6 mg/kg + MEL 10 mg/kg groups prevented these alterations, yielding values comparable to those observed in the Control group. Immunohistochemical analyses demonstrated higher expression of the pro-inflammatory cytokines IL-6 and TNF-α in the livers of animals treated exclusively with bifenthrin, whereas melatonin attenuated this inflammatory response. The results demonstrate that bifenthrin induces hepatotoxicity associated with oxidative stress and inflammation, while melatonin effectively attenuates the hepatic damage induced by this pesticide, highlighting its hepatoprotective potential against bifenthrin exposure and suggesting broader prospects for hepatic protection in different xenobiotic exposure contexts.

COMMITTEE MEMBERS:
Presidente - VALERIA WANDERLEY TEIXEIRA
Interno - ANISIO FRANCISCO SOARES
Externo à Instituição - JAIURTE GOMES MARTINS DA SILVA - UFAL