Purpose To explore the effect of Levothyroxine on spatial working memory in patients with subclinical hypothyroidism (SCH) using blood oxygenation level dependent-functional MRI (BOLD-fMRI). Materials and Methods Sixteen patients with SCH before and after 6 months levothyroxine (LT4) treatment and 16 matched euthyroid volunteers underwent n-back task fMRI scanning. AFNI software was used for localization and quantification. Results All the subjects demonstrated activated areas including bilateral dorsolateral prefrontal cortex (DLPFC), bilateral premotor area (PreMA), supplementary motor area/anterior cingulate cortex, bilateral parietal area (PA) and right caudate nucleus/thalamus, with right hemisphere dominance. Quantitative analysis of regions of interests showed that all these regions had load effect related to memory load in the control group (P<0.001), whereas only left DLPFC, left PA, bilateral PreMA and right caudate nucleus/thalamus showed the same effect in SCH group. After 6-month treatment with LT4, BOLD signal change was observed in SCH patients within the right DLPFC, right PA and anterior cingulate/supplementary motor cortex (P<0.001). The activation intensity of working memory related brain regions was lower in SCH group compared with that of the control group. Conclusion Spatial working memory impairments in SCH patients are likely related to decreased right DLPFC and right posterior parietal function. LT4 replacement therapy is important to improve and reverse the memory impairment.

Aim To study the preventive and therapeutic effects of Buyang Huanwu Decoction(BYHWD)on denervated tibial muscle atrophy of rats.Methods After 60 Sprague-Dawley rats were subjected to Common Peroneal nerve crush model of 5 mm injury, they were randomly divided into 6 groups for daily intragastric administration of drugs:BYHWD high-dose, medium-dose, low-dose groups, mecobalamin group(positive control), model group, sham operation group.The drug administration lasted for 18 days.18 days after operation, slice, masson staining and analysis morphology were performed. The wet weight ratio and section area of tibial muscle were also measured.Results Tibial muscle section area of sham operation group was large, morphous was regular, while that of model group significantly diminished, structure was chaotic, and connective tissue hyperplasia was more obvious;Tibial muscle section area of BYHWD group and mecobalamin group was fairly diminished, morphous was fairly regular, and connective tissue hyperplasia was not obvious.Compared with model group, the section area of BYHWD group all increased significantly(P <0.01)in a dose-dependent manner.Compared with mecobalamin group, the cross section area of BYHWD high-dose group was significantly larger(P <0.05).Compared with model group, the wet weight ratio of BYHWD high-dose and medium-dose group all increased significantly(P <0.01 or P <0.05)in a dose-dependent manner.Conclusion BYHWD has a significant effect of prevention and therapy on denervated tibial muscle atrophy of rats.