Objective:To investigate the mechanism for decrease of glucocorticoid receptor mRNA(GR mRNA)during heat shock response.Methods:The changes of GR mRNA level in SMMC-7721 cells were examined by semi-quantitative RT-PCR during heat shock response.We designed 2 RNA fragments paired with GR gene intron E and cross exon 3,4,and 5,which were used as probes for in situ hybridization with the sequences in SMMC-7721 cells at different periods after heat shock.The result was subjected to confocol microscope observation and computer image analysis.The transcription,degradation,and splicing of GR mRNA were investigated.Results:RT-PCR showed that the GR mRNA level was decreased during heat shock response.In situ hybridization revealed that both GR mRNA and GR pre-mRNA levels were lower in the heat shock group than in the non-heat shock group(P0.05).GR pre-mRNA level was higher in cells treated with actinomycine D before heat shock than in cells only treated with actinomycine D,while the GR mRNA level was lower in cells treated with actinomycine D before heat shock(P0.05).Conclusion:During heat shock response,GR mRNA transcription is suppressed,the splicing of GR pre-mRNA is suppressed,and GR mRNA degradation is accelerated.

Objective:To investigate the changes of alpha adrenergic receptors(α-AR) mRNA expression in heart and mesenteric artery in autonomic dysreflexia(AD) rats after spinal cord transection,so as to explore the possible mechanism of AD.Methods: The spinal cord of rats was exposed and the fourth thoracic spinal cord was transected;4 weeks later,rats' rectum was stimulated by self-made catheter and those with a mean arterial blood pressure increased by more than 15 mmHg(1 mmHg=(0.133) kPa) were chosen as AD group(n=16).Heart and mesenteric arteries along with their branches were harvested.mRNA expression of α_(1A)-,α_(1B)-,α_(1D)-,α_(2A)-,α_(2B)-and α_(2C)-AR was quantified by real time PCR and the result was compared with that in sham-operated group(the fourth thoracic spinal cord was exposed but not transected).Results: Compared with sham-operated group,rats in AD group had a lower expression of α_(1A)-AR mRNA(P0.05) and α_(1B)-AR mRNA(P0.01) in their heart,but the expression of α_(1D)-AR mRNA had no obvious change.Also,rats in AD group had a higer expression of α_(1A)-,α_(1D)-,α_(2B)-AR mRNA(all P0.01) and α_(2C)-AR mRNA(P0.05) in their mesentric artery,but α_(1B)-and α_(2A)-AR mRNA expression had no obvious change.Conclusion: AD may occur in the chronic stage of spinal cord transection in rats.The abnormal expression of α_(1A)-and α_(1B)-AR mRNA in the heart and α_(1A)-,α_(1D)-,α_(2B)-and α_(2C)-AR mRNA in the mesenteric artery may be related to(AD.)

线粒体除作为细胞生成能量的场所,其基因组还编码参与线粒体氧化呼吸链组成的13条多肽链,22种tRNA分子和2种rRNA分子。线粒体基因表达受众多因素调控,其表达异常可影响细胞对氧的利用,与一系列病理生理过程密切相关。该文介绍近年来线粒体基因表达调控,及肿瘤等疾病过程中线粒体基因表达变化的研究进展。

在肝部分切除或创伤后,残存肝组织很快就进入复杂的再生过程.在肝再生过程中,线粒体发挥着重要的作用,不仅提供能量,而且参与细胞的信号转导等活动.近年来众多研究表明,在肝再生过程中线粒体透性转换有明显特征性的变化,并具有一定的规律性;同时发现,在肝再生早期有一些线粒体基质蛋白释放到胞液中,提示线粒体蛋白的释放可能与肝再生之间具有一定的关系.