Abstract: Objective To assess the feasibility of transferring major histocompatibility complex (MHC) gene into the thymus to mitigate xenograft rejection. Methods By molecular cloning technique, we extracted and proliferated the-H-2K d gene from donor mice (MHC class Ⅰ gene of Balb/c mice) and constructed the expression vector plasmid of pCI-H-2K d. Twenty SD rats were selected as receptors, and by using random number table, they were divided into the experimental group and the control group with equal number of rats in each group. By ultrasoundguided puncture and lipofection method, the pCI-H-2Kd was injected into thymus of SD rats in the experimental group and meanwhile, empty vector plasmid of pCIneo was injected into thymus of SD rats in the control group. Subsequently, we transplanted the donor mice myocardium xenografts into the receptor rats, and observed the xenograft rejection in both the two groups. Results The survival time of the xenotransplanted myocardium in the experimental group was significantly longer than that in the control group (14.61±2.98 d vs. 6.40±1.58 d, t=-7.619,Plt;0.05). Microtome section of transplanted myocardium in the control group showed a relatively large amount of lymphocyte infiltration and necrosis occurred to most part of the transplanted myocardium, while microtome section of experiment group showed no lymphocyte infiltration and most of the cells of the transplanted myocardium were still alive. After mixed lymphocyte culture, the reaction of receptors to donor cells in the experiment group was obviously lower than that in the control group (t=4.758, P=0.000).After the count by flow cytometer, the xenoMHC molecules were expressed in the receptors’ thymus with a transfection efficiency of 60.7%. Conclusion Our findings suggest that xenograft rejection can be mitigated substantially by donor’s MHC gene transferring into receptor’s thymus. This may provide theoretical and experimental evidence for inducing xenotransplantation tolerance.
Inherited retinal degeneration (IRD) is a group of fundus diseases characterized by a high degree of genetic heterogeneity and clinical heterogeneity, and more than 300 genetic mutations have been identified in association with IRD. Dysregulation of the intracellular second messenger cyclic guanosine monophosphate (cGMP) plays an important role in the development of IRD. cGMP participates in phototransduction process in photoreceptors. Abnormally elevated cGMP over-activate protein kinase G and cyclic nucleotide-gated channel, causing protein phosphorylation and Ca2+ overload, respectively, and these two cGMP-dependent pathways may individually or collectively drive photoreceptor degenerative lesions and death; therefore, reducing cGMP synthesis and blocking downstream signaling can be considered as treatment strategies. Investigating the molecular mechanisms of cGMP dysregulation in photoreceptor degeneration may provide a more comprehensive picture of the pathogenesis of IRD, as well as ideas for finding new therapeutic targets and designing therapeutic programs.
Objective To observe the changes of inflammatory cytokines in brain protective methods, study the inflammatory mechanism during cerebral protection tissues in different cerebral Methods Eighteen healthy adult dogs were randomly divided into three groups （6 dogs in each group）： normothermic cardiopulmonary bypass （NCPB group）, deep hypothermic circulatory arrest （DHCA group）, and intermittent selective antegrade cerebral perfusion （ISACP） during DHCA（DHCA＋ISACP group）. After operation the water contents in brain tissue were measured ,the hippocampus were removed, and radio-immunity analysis （RIA） was used to measure the content of interleukin-1β（IL-1β） and tumor necrosis factor-alpha （TNF-α） of the hippocampus tissue. The morphology of the hippocampus were examined by transmission electron （TE） microscopy. Results The contents of IL-1β and TNF-α of DHCA group was higher significantly than those of NCPB group and DHCA＋ISACP group （P〈0.01）, there was no significant difference between NCPB group and DHCA＋ISACP group （P〉0.05）. And the contents of TNF-α and IL-1β were positive linear correlated with degree of edema of brain tissues （r = 0. 987, 0.942; P〈 0.01）. TE examination revealed that the damage of the uhrastructure in the DHCA group was more severe than that in NCPB group and DHCA＋ISACP group. Conclusions This experiment revealed that long duration DHCA can bring some damages to the brain and that ISACP during long-term DHCA has brain protective effects to some extent. IL-1β and TNF-α play an effective role in the brain damage of long-term DHCA.
