Objective To investigate the effect of hypothermia on the learning and memory a-bility of neonatal rats during anesthesia and its possible mechanism.Methods Forty SD rats aged 7 d were randomly divided into 4 groups (n=10):control group (group C),anesthesia group (group A),anesthesia and hypothermia group (group AH),hypothermia group (group H).Group C was in-jected intraperitoneally with 0.1 ml of saline and equipped with heating pad to keep the rectal temper-ature at 38-39℃.Group A was injected with propofol 0.1 ml at 25 mg/kg intraperitoneally with 1/2 of the initial dose,and anesthesia was maintained for 2 h.The same method to maintain the rectal temperature at 38-39℃;Group AH of anesthesia and time and Group A of the same,rats in the anes-thesia process is not insulation,control room temperature of 23℃,allowing the body temperature de-creased;Group H rats intraperitoneal injection of 0.1 ml saline,the same control room temperature of 23℃,so that the natural temperature drop.Anesthesia in the process of continuous oxygen,inter-mittent monitoring of body temperature.Immediately after awake,5 rats in each group were randomly selected to detect the content of p-ERK and p-CREB in hippocampus by Western blot.The spatial learning and memory ability and p-ERK and p-CREB contents in hippocampus were measured by water maze test.Results The rectal temperature in group AH and group H decreased to (25.38± 0.22)℃ and (25.54±0.20)℃ in 1 h respectively,and the body temperature decreased significantly compared with group C(38.36±0.24)℃ and group A(37.40±0.29)℃ (P<0.05).Compared with group C and group A,the expression of group AH and group H was decreased (P<0.05).At the end of the water maze test,the expression of protein in the four groups was not statistically signifi-cant.There was no significant difference between the four groups in the escape latency,the number of crossing the platform and the quadrant of the original platform quadrant.Conclusion The expression of p-ERK and p-CREB in neonatal rats hippocampus can be short-term inhibition in the period of hy-pothermia at 25℃,but no significant effect on the long-term learning and memory ability.

Scaffold-free tissue engineered cell sheet is an emerging technology in biomedical field. It can avoid the adverse effects of scaffold materials, and can be further assembled to form more complex three-dimensional functional tissues. The construction of cell sheet is mainly based on the culture substrate composed of sensitive materials. By changing the stimulation factors such as temperature, enzyme, light, ion, redox, pH and sugar, the adhesion behavior of the substrate to the cells could be changed to make the cells detach naturally, thus generating the cell sheet. Recent years have seen the development of various simple and efficient construction technologies of cell sheet due to the development of a variety of novel sensitive culture substrates. The resulted cell sheets with excellent performance have greatly expanded their applications. This review summarized the construction methods of tissue engineered cell sheet and discussed the challenges and future perspectives in this field.
Temperature ; Tissue Engineering ; Tissue Scaffolds