Sex comparison of oxidative stress, mitochondrial dysfunction, and apoptosis triggers induced by single-dose Abamectin in albino rats.

Abamectin (AB) is widely used in agriculture and has been employed as an insecticide, nematicide, and livestock pest control agent. However, it may also pose a serious threat to mammals. The primary purpose of this research was to compare the sex variations between male and female rats during exposure and to assess the risk of toxicity of abamectin, which are still largely unknown. The twenty albino rats were divided randomly into four groups (n = 5): 1) the male control group; 2) the male treatment group treated with AB (1 mg/kg B.W.); 3) the female control group; and 4) the female treatment group treated with AB (1 mg/kg B.W.). AB administration caused a drop in body weight in females more than males with showing oxidative stress in both sexes of animals, as characterized by an increase in MDA content and a decrease in glutathione (GSH) content and superoxide dismutase (SOD) activity. Reported sex-specific effects suggested that females are more susceptible from males in brain tissues for alteration of antioxidant markers while females' liver and kidney tissues showed more level of lipid peroxidation than males. In addition, mitochondrial dysfunction was associated with a significant decrease in NADH dehydrogenase (Complex I) and a significant decrease in mitochondrial ATPase, which led to apoptosis and histopathological alterations in the targeted tissues, indicating that females are higher sensitive than males to these biological events. In brief, the results of this study led to female rats are generally more sensitive than male rats to neurobehavioral and hepatic complications associated with abamectin treatment. Further evaluation should be performed to determine the adverse outcome pathways involved and to determine the effects of sex on improving the risk assessment of abamectin in both sexes.

Differential Recruitment of the Infralimbic Cortex in Recent and Remote Retrieval and Extinction of Aversive Memory in Post-Weanling Rats.

BACKGROUND: We previously showed that the infralimbic medial prefrontal cortex (IL-mPFC) plays an important role in recent and remote memory retrieval and extinction of conditioned odor aversion (COA) and contextual fear conditioning (CFC) in adult rats. Because the mPFC undergoes maturation during post-weaning, here, we aimed to explore (1) whether post-weanling rats can form recent and remote COA and CFC memory, and (2) the role of the IL-mPFC in mediating these processes. METHODS: To investigate the retrieval process, we transiently inactivated the IL-mPFC with lidocaine prior to the retrieval test at either recent or remote time points. To target the consolidation process, we applied the protein synthesis inhibitor after the retrieval at recent or remote time points. RESULTS: Our results show that the post-weanling animals were able to develop both recent and remote memory of both COA and CFC. IL-mPFC manipulations had no effect on retrieval or extinction of recent and remote COA memory, suggesting that the IL has no effect in COA at this developmental stage. In contrast, the IL-mPFC played a role in (1) the extinction of recent, but not remote, CFC memory, and (2) the retrieval of remote, but not recent, CFC memory. Moreover, remote, but not recent, CFC retrieval enhanced c-Fos protein expression in the IL-mPFC. CONCLUSIONS: Altogether, these results point to a differential role of the IL-mPFC in recent and remote CFC memory retrieval and extinction and further confirm the differences in the role of IL-mPFC in these processes in post-weanling and adult animals.

Dissociation of the Role of Infralimbic Cortex in Learning and Consolidation of Extinction of Recent and Remote Aversion Memory.

Medial prefrontal circuits have been reported to undergo a major reorganization over time and gradually take a more important role for remote emotional memories such as contextual fear memory or food aversion memory. The medial prefrontal cortex, and specifically its ventral subregion, the infralimbic cortex (IL), was also reported to be critical for recent memory extinction of contextual fear conditioning and conditioned odor aversion. However, its exact role in the extinction of remotely acquired information is still not clear. Using postretrieval blockade of protein synthesis or inactivation of the IL, we showed that the IL is similarly required for extinction consolidation of recent and remote fear memory. However, in odor aversion memory, the IL was only involved in extinction consolidation of recent, but not remote, memory. In contrast, only remote retrieval of aversion memory induced c-Fos activation in the IL and preretrieval inactivation of the IL with lidocaine impaired subsequent extinction of remote but not recent memory, indicating IL is necessary for extinction learning of remote aversion memory. In contrast to the effects in odor aversion, our data show that the involvement of the IL in the consolidation of fear extinction does not depend on the memory age. More importantly, our data indicate that the IL is implicated in the extinction of fear and nonfear-based associations and suggest dissociation in the engagement of the IL in the learning and consolidation of food aversion extinction over time.