| Objective The purpose was to explore the change of gastric emptying as well as enteric glial cells in stomach with different courses of vagotomized rats.Methods Thirty male SD rats,weighted 250-350g,were divided into three groups randomly.There were control group(N= 10),early subdiaphragmantic vagotomy(ESDV,7 days,N=10)and terminal subdiaphragmatic vagotomy(TSDV,56 days,N=10).Gastric emptying was detected by phenol red test meal,which was used to evaluate the change of gastric motility.RT-PCR,immunofluorescence and transmission electron microscope(TEM)methods were used to observe the mRNA and protein levels of GFAP and S100B.,and the ultrastructural change of enteric glial cells.Results(1)Compared with control group,gastric emptying was accelerated in ESDV group,but had no statistically significant;gastric emptying was significantly delayed in TSDV group than that in ESDV group.(2)Compared with control group and ESDV group,the expression of GFAP mRNA significantly decreased in TSDV group;compared with ESDV group,the expression of S100B mRNA was obviously lower in TSDV group;there was no difference in the expression of GFAP and S100B mRNA between control group and ESDV group.(3)The expression of GFAP and S100B protein were significantly decreased in TSDV group than that in ESDV group and control group;there was no significant difference between ESDV and control group.(4)In ESDV group and TSDV group,the ultrastructure of enteric glial cells was damaged.The results were showed that mitochondrions were swollen,endoplasmic reticulum was dilated and numbers of intermediate filaments were decreased.Conclusion In the vagotomized rats,gastric emptying was delayed and the structure and function of enteric glail cells were impaired.However,enteric glial cells have certain compensatory ability.Aim To investigate the change of GDNF and its downstream signaling pathway PI3K/Akt in vagotomized rats.Methods The vagotomized rat model was established.The protein expression of GDNF、Cx43、p-Akt、pan-Akt and PGP9.5 were detected by western blot;GDNF、Cx43、pan-Akt and PGP9.5 mRNA expression were measured by RT-PCR;immunofluorescence was used to observed the protein expression of GDNF、GFAP and PGP9.5.TUNEL was applied to evaluate apoptosis.Results(1)Compared with control group,GDNF,Cx43,and PGP9.5 protein expression were significantly decreased in early vagotomized group;protein expression of p-Akt and pan-Akt in each group had no significant difference.(2)Compared with control group,GDNF,Cx43 and PGP9.5 mRNA expression in early and terminal vagotomized groups were significantly lower.However,pan-Akt mRNA expression in early and terminal vagotomized groups was higher than that in control group.(3)GDNF and GFAP were located in EGC.Compared with control group,GDNF、GFAP and PGP9.5 protein expression were significantly decreased in early and termianl vagotomized groups.(4)There were fewer TUNEL(+)cells in control group,while the number of TUNEL(+)cells was significantly increased in both early and terminal vagotomized groups.Conclusion GDNF and its downstream PI3K/Akt signaling pathway were impaired in the vagotomized rats and the apoptosis cells were significantly increased in gastric tissues.Aim To explore the effect of synchronized dual pulse gastric electrical stimulation(SGES)on gastric motility and EGC in vagotomized rats,and further to investigate the possible regulatory mechanism.Methods A total of fifty male SD rats were divided into five groups.There were normal control group(control,N=10),early subdiaphragmatic vagotomized group(ESDV,2 weeks,N=10),early subdiaphragmatic vagotomized group + short-term synchronized dual pulse gastric electrical stimulation(ESDV+SSGES,30 min/day,2+2 weeks,N=10),terminal subdiaphragmatic vagotomized group(TSDV,4 weeks,N=10),terminal subdiaphragmatic vagotomized group + long-term synchronized dual pulse gastric electrical stimulation(TSDV+LSSGES,30 min/day,4+6 weeks,N=10).Synchronized dual pulse gastric electrical stimulation consisted of a long pulse(300 ms,4 mA)and five short pulses(0.33 MS,4 mA,100 Hz).Phenol red test meal was used to measure gastric emptying for evaluating gastric motility.Further,the study observed the expression of Cx43、GDNF、p-Akt、pan-Akt and PGP9.5 by western blot and RT-PCR,the localization and expression of GDNF,GFAP and PGP9.5 by immunofluorescence,the ultrastructural changes of EGC by transmission electron microscopy and apoptosis by TUNEL.Results(1)Compared with control group,the gastric emptying was obviously accelerated in ESDV group and delayed in TSDV group.LSGES obviously improved delayed gastric emptying compared with TSDV group,.(2)Western blot showed that protein expression of Cx43 was significantly decreased in ESDV and TSDV groups,but both SSGES and LSGES could obviously increased its expression;compared with control group,SSGES and LSGES can significantly increase GDNF expression,but the effect of LSGES was better than SSGES;LSGES obviously increased the expression of p-Akt compared with that in TSDV group;expression of pan-Akt had no significant difference in each group;compared with control group,expression of PGP9.5 was significantly decreased in ESDV group,but SSGES obviously increased its expression.(3)The Cx43,GDNF and PGP9.5 mRNA expression were significantly decreased in ESDV and TSDV groups,but both SSGES and LSGES could obviously increase their expression.(4)Immunofluorescence showed that GDNF was located in EGC and its expression was decreased in the ESDV and TSDV groups;to a certain extent,SSGES and LSGES increased expression of GDNF;expression of PGP9.5 decreased in ESDV and TSDV groups and increased in SSGES group and LSGES groups.(5)TUNEL showed that there were more TUNEL(+)cells in ESDV and TSDV groups compared with control group,while LSGES and SSGES could significantly reduce the TUNEL(+)cells.(6)Transmission electron microscope showed that the normal EGC contained abundant mitochondria,smooth and rough endoplasmic reticulum,intermediate filaments;there were swelling of mitochondria,dilated endoplasmic reticulum,and reduced number of intermediate filaments in ESDV and TSDV groups;SSGES and LSGES improved the damaged EGC by increasing the number of mitochondria and intermediate filaments,and reducing the swelling of endoplasmic reticulum.Conclusion SGES effectively improved delayed gastric emptying in vagotomized rats;at the same time,it could restore structure and function of the injured EGC,and upregulate GDNF expression and its downstream PI3K/Akt signaling pathway. |
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