Effects Of Different P_ETCO₂ On Postoperative Function Of Learning And Memory In Child Rats Undergoing CO₂ Pneumoperitoneum

Objective:To observe Effects of different PETCO2 on postoperative function of learning and memory in child male rats undergoing CO2 pneumoperitoneum.Methods:Thirty child rats(5-6weeks old,weight 150-180g)scheduled for CO2 Pneumoperitoneum undergoing endotracheal intubation general anesthesia.All of rats were randomly divided into three group(Group S,N and H).Group S(n=10)no pneumoperitoneum;Group N(n=10)control PETCO2 in the normal range of 40-45mmHg during operation through the modulating of respiratory parameters after pneumoperitoneum;Group H(n=10)control PETCO2 in the high range of 60-65mmHg during operation through the modulating of respiratory parameters after pneumoperitoneum.Pneumoperitoneum time is 90 minutes.Record postoperative 1d to 4d Morris water maze experiment escape latency time and postoperative 2h HE staining slices and NSE immunohistochemical staining slices in brain hippocampus of rats.Statistical processing:analysis was performed using SPSS 16.0 statistical software,the measurement data were showing by mean±standard(x±s),two independent samples t test was used for the between-group comparisons statistical analysis,the intragroup comparisons were analyzed with wariance for repeated measurement design,with P<0.05 was statistically significant.Results:Compared with Group S,there was no difference in the average escape latency time in the first day,the second day,the third day and the fourth day in Group N,there was no statistically significant difference(P>0.05);Compared with Group S,average escape latency time in first day,the second day,the third day and the fourth day were increased obviously in Group H,there were statistically significant(P<0.05);Compared with Group N,average escape latency time in first day,the second day,the third day and the fourth day were increased obviously in Group H,there was statistically significant(P<0.05).In HE staining slices,cells were circular or oval,nucleus were large and round,color was light,nuclear membrane and nucleolus were obvious,arrangement was close and regular,cell boundaries were clear in rat brain hippocampus of Group S;Compared with Group S,there were no obvious difference in rat brain hippocampus of Group N;Cells shape were irregular,color was a bit deep,arrangement was loose and confused,cell boundaries were unclear in rat brain hippocampus of Group H.In NSE immunohistochemical staining slices,immunohistochemical reaction was negative,the color of background was light blue in rat brain hippocampus of Group S;Compared with Group S,there were no obvious difference in rat brain hippocampus of Group N;immunohistochemical reaction was weak or moderate positive and immune complex was brown in color in rat brain hippocampus of Group H.Conclusion:High PETCO2(60-65mmHg)could cause adaptive change of brain hippocampus cells postoperative CO2 pneumoperitoneum of child rats;High PETCO2(60-65 mmHg)could cause the increase of the average escape latency time of 1 to 4 days Morris water maze experiment postoperative CO2 pneumoperitoneum of child rats and could result in postoperative dysfunction of learning and memory of child rats.