Long-term diabetic hyperglycaemia modifies social behaviour in rats

Diabetes is a known risk factor for cognitive decline and mood disorders. However, the effects of long-term diabetic hyperglycaemia on the various dimensions of social behaviours, such as play or aggression, remains to be fully elucidated. In this study, we evaluated the social behaviour in a nicotinamide-streptozotocin rat model of long-term diabetic hyperglycaemia, in the absence of glucose-lowering treatments. Five months following induction of hyperglycaemia, we scored affiliative/exploratory or aggressive social interactions between pairs of unacquainted rats in a neutral arena. Our results demonstrate alterations in the behaviour of long-term diabetic rats faced with social novelties. Specifically, diabetic hyperglycaemic rats engaged in hyper-sociable and hyper-aggressive encounters. Interestingly, social interactivity was not associated with the degree of hyperglycaemia in affiliative/exploratory or in aggressive social interactions, in our long-term diabetic rat model. Altogether, our data suggest a lack of social appropriateness in long-term diabetic hyperglycaemic rats which is independent of the degree of hyperglycaemia. These findings support the importance of a tight glycaemic control in the management of diabetes at every stage of the disease and enlighten the importance of impaired glycaemic control as a novel metabolic player impacting the neural networks of social behaviours.