The Individual Variation Study Of Electro-acupuncture Analgesia And Recovery Speed From Restraint Stress In Rats Using Microarray

Partâ… .An individual variation study of electroacupuncture analgesia in rats using microarrayObjective:The aim of the present study is to probe candidate genes which were involved in the electro-acupuncture(EA) analgesia and to understand the molecular basis of the individual difference of EA analgesia in rats.Methods:EA stimulation at the ST36 acupoints(Zusanli) was applied for 1h at 1Hz and nociceptive sensitivity was assessed by recording the tail-flick latency(TFL) induced by radiant heat.Responders and non-responders were determined by Pain Threshold Increase Rate(PTIR) in which the PTIR of responders is more than 30%while the PTIR of non-responders is less than 25%of control.We compared hypothalamus transcriptional profiles of responders with that of non-responders using oligonucleotide microarray.A half dye-swap design was applied so that half of the responder to non-responder comparisons are Cy3 to Cy5 and the other half are Cy5 to Cy3.Differential expressed genes were filtered using Significance Analysis of Microarrays(SAM) software package.Based on their biological function,the differential expressed genes were classified into different functional groups using GeneTools online software.At last,a real-time quantitative RT-PCR was applied to validate selected differential expressed genes.Results:First,our results confirmed the individual variation of EA analgesia,there were about 30%animals showed no analgesia effect.Second,we found that 63 and 3 genes were up- and down-regulated in the responder group with the least fold change 1.54, respectively.Third,half of the differentially expressed genes were classified into 9 functional groups which were ion transport,sensory perception,synaptogenesis and synaptic transmission,signal transduction,inflammatory response,apoptosis,transcription, protein amino acid phosphorylation and G-protein signaling.Fourth,Quantitative RT-PCR results confirmed the microarray data.Conclusion:Our study confirmed the individual difference of EA analgesia,this maybe result from the differential expressions of related genes in rat hypothalamus which were found in our study.These genes may become new targets for nociceptive study and deserve further investigation for developing new acupuncture therapy and intervention of pain modulation. Partâ…¡.An individual variation study of recovery speed from restraint stress in rats using microarrayObjective:The aim of the present study is to search novel genes which maybe involved in the recovery process after restraint(RES) stress in rats.Methods:Using rat restraint stress model,blood samples were taken just before the exposure to RES,at the end of RES,1h after the termination of RES using tail-nick method. Plasma corticosterone and ACTH were measured using enzyme linked immunosorbent assay(ELISA) and radioimmunoassay(RIA),respectively.Based on the plasma corticosterone and ACTH levels at the end of RES,the RES rats were divided into high response group and low response group.Animals within the high response group were then divided into fast recovery group or slow recovery group which was determined by the decline of plasma ACTH and corticosterone levels during one hour recovery period after stress.We compared hypothalamus transcriptional profiles of two different recovery patterns(fast recovery vs slow recovery) from restraint stress in rats using oligonucleotide microarray.A half dye-swap design was applied so that half of the slow-to-fast recovery comparisons are Cy3 to Cy5 and the other half are Cy5 to Cy3.A special variation customized normalization for this data set was applied.A fixed effect ANOVA model was used for analyzing microarray data.A real-time quantitative RT-PCR was applied to validate the differential expressed genes.Results:First,our results demonstrated that there is significant difference of plasma corticosterone and ACTH levels after 2h RES stress,that is,some individual had high response while others had low response for stress.Also,a significant difference were found between fast recovery group or slow recovery group concerning plasma ACTH and corticosterone levels during one hour recovery period after stress.Second,analysis of the microarray data showed that most of genes are not differentially expressed between fast VLA-6(integrin alpha-6 precursor) and Myosin IXb were at least 1.5 fold up-regulated in fast recovery group,while junctional adhesion molecule 1(Fllr) was 1.5 fold down-regulated in fast recovery group.Third,quantitative RT-PCR results confirmed the microarray data.Conclusion:The present study demonstrated that different individual had different stress response even if they experienced same stressor.Meanwhile,the recovery process of restraint stress was also different.As it is not yet proved whether integrin signaling pathway was involved in the recovery from restraint stress in rats,further study will be needed to clarify the integrin signaling pathway-mediated recovery mechanism after stress.