TNF-α receptor antagonist attenuates isoflurane-induced cognitive impairment in aged rats

Postoperative cognitive dysfunction (POCD), a common clinical in aged patients, is characterized by deficits in cognitive functions in patients following anesthesia and surgery. It has been demonstrated that isoflurane may lead to cognitive impairment in aged rats; however, effective clinical interventions for preventing this disorder are limited. Tumor necrosis factor (TNF)-alpha has been suggested to be involved in neuroinflammation as well as the development of POCD. Accordingly, the present study aimed to investigate whether TNF-alpha signaling is involved in the isoflurane-induced cognitive impairment in aged rats, and whether TNF-alpha receptor antagonist are able to attenuate isoflurane-induced cognitive impairment in aged rats. A population of 20-month-old rats were administered TNF-alpha receptor antagonist R-7050 or an equal volume of saline by intraperitoneal injection 12 h prior to exposure to isoflurane to model cognitive impairment following anesthesia in old patients. Then the rats were exposed to 1.3% isoflurane for 4 h. In the control group, rats showed impaired cognitive functions evaluated by Morris water maze assay after isoflurane exposure. Furthermore, isoflurane exposure induced marked upregulation of proinflammatory cytokines, including interleukin (IL)-1 beta, TNF-alpha, IL-6 and IL-8 in the hippocampus tissue. In the experimental group, intracisternal administration of TNF-alpha receptor antagonist R-7050 significantly attenuated isoflurane-induced cognitive impairment and upregulation of proinflammatory cytokines. Further investigation revealed that intracisternal administration of TNF-alpha receptor antagonist R-7050 notably suppressed isoflurane-induced activation of NF-kappa B and MAPK signaling. Collectively, the present results suggest that TNF-alpha receptor antagonist may serve as a potential agent for the prevention of anesthesia-induced cognitive decline in aged patients.