Evaluation of Empathetic Behavior Following Post Aluminum Exposure in Rat Model

Abstract

Empathy is a complex psychological attribute, described as a natural, complex cognitive, and emotional ability to recognize and be responsive to emotional condition of a different person, as well as a desire to care for their well-being. Contaminated drinking water is an emerging problem faced by the world, especially in developing countries. Isolation has also been found to have an impact on comfortable lifestyle. So the current study was designed to investigate the role of social isolation, post Aluminum (Al) exposure on regulation of empathy in female Wistar rats. The animals were categorized into five groups (recovery control , post Al exposure, recovery isolation, post Al exposure + isolation and Subject) (n=10) and the rat model was developed by giving 80 mg/Kg Al chloride (AlCl3) in drinking water for 40 days. This was followed by the recovery phase (40 days), in which distilled water was given to rats. The model for Empathy behavior test (EBT) implied the use of restrainer stress method. Moreover, anxiety and stress levels were measured by Elevated plus maze (EPM) and grooming behavior respectively. The assessment through elevated plus maze revealed the number of entries made by post Al exposure group on day 17th (2.7 ± 0.3) and day 37th (2.4 ± 0.22) of recovery was not considerably different from the control group but a significant difference (p<0.05) has been seen in post Al exposure + isolation group on day 17th (3.4 ± 0.34) and day 37th (4.8 ± 0.29) of recovery. The duration spent in open arms revealed that anxiety which was activated by an existing stimuli is self-recovered as there was a significant difference (p< 0.0001) found in the number of entries made by the post Al exposure group on day 17th (5.8 ± 0.25) and day 37th ( 9.2 ± 0.33) of recovery. Similar pattern was observed with isolated animals. In order to evaluate stress like behavior in rats, grooming behavior test was performed. Number and duration of correct and incorrect grooming bouts along with latency to start grooming were taken as parameters ABSTRACT ix to analyze level of stress. It was observed that the stress level is not reduced in grouped and isolated rats after post Al exposure. The duration of correct grooming bouts in post Al exposure group and post Al exposure + isolation group was significantly less (p< 0.0001) in contrast to control groups. The result is parallel with duration of incorrect grooming bouts which is greater (p< 0.0001) on day 37th as compared to day 17th of recovery. Empathy behavior test (EBT) was performed using a modified protocol of restrainer method. The parameters used to evaluate empathy behavior were number of interactions and climbing the restrainer in which the subject was enclosed. The duration spent in close proximity and duration of freezing bouts were also analyzed. The time in close proximity by all groups in first five minutes of testing phase of EBT was significantly more (p< 0.0001) than rest of phases. The empathy was found to be recovered as the number of climbing and interaction were non-significantly different than their respective control groups. Similar pattern was observed in the duration of freezing behavior in post Al exposure group after long term. This study provided the evidence that empathetic behavior can be elicited by restrainer stress model and that metal exposure and social isolation are associated with the disruption in the neural circuitry of empathy. Therefore further elucidation of the molecular, biochemical, and neurological patterns is required to unravel the exact phenomenon of empathy.