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High-fat diet exacerbates postoperative pain and inflammation in a sex-dependent manner
Despite the links between obesity and experiencing elevated levels of pain, our understanding regarding the impact of obesity and diet on postoperative pain remains insufficient. In this study by Song et al. (2018), the authors investigated the impact of obesity and diet by using the paw incision model (designed to investigate postoperative pain) in a population of Long-Evans rats, fed either a high-fat or a low-fat diet for a period of six weeks prior to the start of the experiment. The authors observed an increase in pain response and in the duration of overall hypersensitivity to pain upon conducting paw incisions in male rats receiving a high-fat diet compared to controls, however, female rats did not show the same propensities. Secondly, the authors noted that eliminating the high-fat diet for a period of two weeks prior to the paw incision procedure ameliorated the dietary derangement of pain behaviors despite the persistence of the weight gained. Moreover, the exposure to a high-fat diet for a short period of one week prior to the paw incision procedure led to an increase in observed pain behaviors, an impact that was noted to be of lesser magnitude compared to the six-week experimental exposure. From a cellular level, the authors noted an increase in lumbar dorsal root ganglion macrophage population and increased sensitivity of peritoneal macrophages to lipopolysaccharide with the administration of the high-fat diet for six weeks in male rats compared to controls. Finally, high-fat diet rats were noted to have higher skin levels of the nerve regeneration marker growth-associated protein 43 (GAP43) and retarded wound healing, compared to controls. The authors conclude that a high-fat diet worsens postoperative pain, especially in male rats, and that this dietary impact is not entirely associated with the weight gained, as short-term dietary exposure led to deranged pain responses that were not associated with significant obesity. [NPID: Postoperative pain, high fat diet, obesity, rats, animal]
Year: 2018
