The Effect Of Acute Injury By Hepatectomy On Spatial Learning And Memory In Mice

Postoperative cognitive dysfunction (POCD) is a common central nervous system complication after major surgery. It refers to deficits of personality, social skills, cognitive function and skills, often characterized by injury involving memory and concentration. That can be detected through neuropsychological test. A higher incidence of POCD in elderly patients, mostly are temporary, few are long-term cognitive impairment even permanent cognitive impairment, especially after major surgery. With the population aging process, improved surgical techniques and anesthesia management, more opportunities for the elderly undergoing surgery.That will greatly increase the incidence of POCD and Mortality. The occurrence of POCD is associated with postoperative recovery of patients, prolonged hospital stay, increased incidence of postoperative complications and mortality. Not only effects quality of life, also increased Economic burden on families and society, The medical and social problems are worsening. Prevention of POCD is an urgent status. However, the pathophysiology of POCD remains unclear. studies had suggested that inflammation plays a major role in the pathogenesis of POCD. The surgical trauma and stress induced inflammation is an important pathophysiological changes in perioperative. TLR4 (Toll Like Receptor 4) is an important factor in innate immune activation, In tissue trauma and stress, TLR4 identified endogenous ligands including heparin degradation products,tissue trauma products and so on. involved in aseptic inflammatory response. However, this immune response whether involved in the formation of POCD is not known. We first proposed that TLR4-mediated inflammatory response involved in the formation of POCD. This will help to explore the pathogenesis of POCD in Theory.Therefore, We undertook a study develop a model of cognitive dysfunction (partial hepatectomy). Observed effects of anesthesia and surgery on spatial learning and memory, Explore the role of TLR4-mediated inflammatory response in The formation of cognitive dysfunction.Materials and methods:A total of 90 mice were selected through Morris water maze training for four days. them were randomly divided into three groups. control group (group A, n=30): neither anesthesia nor surgery was performed; anesthesia group (group B, n=30): general anesthesia was administrated(fentanyl(0.2mg/kg) and droperidol(5mg/kg) intraperitoneal injection);surgery Group (group C, n=30) partial hepatectomy was performed under general anesthesia. Each major group was randomly subdivided into three subgroup(n=10).Morris water maze spatial probe was performed after anesthesia or surgery 1,3,7 day.The expressions of TLR4, TNF-a and IL-1βmRNA in hippocampus were detected by real-time PT-PCR.Results:1. Compared to group A1 and group B1, the water maze escape latency was significantly higher in group C1 (P<0.01). Compared to group A3 and group B3, the water maze escape latency was significantly higher in group C3 (P<0.05). The e water maze escape latency was no significant differences among the group A7,group B7 and group C7 (P> 0.05).2. Compared to group A1 and group B1,TLR4, TNF-a, IL-1βmRNA expression were significantly higher in group C1(P<0.05). Compared to group A3 and group B3, TLR4, TNF-a, IL-1βmRNA expression were significantly higher in group C3 (P<0.05). TLR4, TNF-a, IL-1βmRNA expression were no significant differences among the group A7, group B7 and group C7. Conclusion:1 Partial hepatectomy impaires spatial learning and memory ability of mice.2 Surgical trauma produce significant effect on spatial learning and memory function in mice, That may be related to TLR4,TNF-αand IL-1βmRNA expression increased in the hippocampus.