Clinical effects and mechanisms of a Chinese patent medicine, Tongxinluo capsule, as an adjuvant treatment in coronary heart disease.

Coronary heart disease (CHD) is the leading cause of death globally, posing a serious threat to human health. However, the current treatment approaches available for CHD fall short of the ideal results. Tongxinluo (TXL) is a traditional Chinese medicine (TCM) that has been employed in the clinical treatment of cardiovascular and cerebrovascular diseases (such as angina pectoris, stroke, etc.) in China for many years and holds great potential as a prospective treatment. TXL either as a standalone treatment or in combination with interventions recommended in CHD guidelines has been shown to be effective and well tolerated in clinical trials for CHD. Drawing on the evidence from clinical trials and experimental studies, this review will focus on the cardiovascular protective properties and related mechanisms of TXL. By searching 8 Chinese and English databases, more than 4000 articles were retrieved. These articles were categorized, then read, and finally written into this review. In this review, the pharmacological properties of TXL include regulation of blood lipids, improvement of endothelial function, anti-inflammatory, antioxidant, inhibition of apoptosis and regulation of autophagy, anti-fibrosis, promotion of angiogenesis, and modulation of exosome communication. The information provided in this review will help the reader to comprehend better the insights that TCM has developed over time in practice and provide new perspectives for the treatment of CHD.

Efficacy and safety of tongxinluo capsule for angina pectoris of coronary heart disease: an overview of systematic reviews and meta-analysis.

Background: Tongxinluo capsule (TXLC) is a common drug for treating angina pectoris of coronary heart disease (CHD). In recent years, many systematic reviews (SRs) and meta-analyses (MAs) have reported the efficacy and safety of TXLC for improving angina symptoms in patients with CHD. We aimed to comprehensively evaluate the existing SRs and MAs of TXLC in treating angina pectoris of CHD, summarize the evidence quality, and provide scientific evidence and recommendations. Methods: We searched seven databases for relevant SRs/MAs published up to 1 June 2023. Two reviewers independently completed the literature retrieval, screening, and data extraction. We used A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) to evaluate the methodological quality, the Risk of Bias in Systematic Reviews (ROBIS) to assess the risk of bias, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) to determine the strength of the evidence. RevMan 5.3 was used to synthesize data. Results: We identified 15 SRs/MAs, including 329 RCTs and 33,417 patients. According to the evaluation results of AMSTAR-2, only one SR was of high methodological quality, the others were very low. ROBIS assessment showed that one SR (6.67%) had a low risk, 3 SRs (20%) had an unclear risk, and 11 SRs (73.33%) had a high risk. We assessed 42 outcomes by the GRADE, 10 (23.81%) for moderate-quality evidence, 17 (40.48%) for low-quality evidence, and 15 (35.71%) for very-low-quality evidence. Mate-analysis showed that TXLC combined with conventional western medications improved electrocardiogram efficacy (RR = 1.38, 95% CI: 1.23-1.43, P < 0.001) and angina efficacy (OR = 3.58, 95% CI: 3.02-4.24, P < 0.001), reduced angina attack frequency (SMD = -0.54, 95% CI: -0.64 to -0.44, P < 0.001) and angina duration (SMD = -0.42, 95% CI: -0.57 to -0.28, P < 0.001), with general heterogeneity. The pooled results showed that TXLC appears to have some efficacy in improving cardiac function and relieving angina symptoms, but there is limited evidence that it improves cardiovascular event rates, hemorheology, lipids, or hs-CRP. In the assessment of drug safety, TXLC was associated with different degrees of adverse drug reactions. Conclusion: Based on the evidence, TXLC may be effective as an adjuvant treatment for angina pectoris of CHD. However, the quality of the evidence is low, and the drug's safety must be carefully interpreted. In future studies, high-quality randomized controlled trials are needed to confirm the effectiveness and safety of TXLC. Systematic Review Registration: http://www.crd.york.ac.uk/PROSPERO/, identifier (CRD42022365372).

Inhibiting leukocyte-endothelial cell interactions by Chinese medicine Tongxinluo capsule alleviates no-reflow after arterial recanalization in ischemic stroke.

AIMS: Despite successful vascular recanalization in stroke, one-fourth of patients have an unfavorable outcome due to no-reflow. The pathogenesis of no-reflow is fully unclear, and therapeutic strategies are lacking. Upon traditional Chinese medicine, Tongxinluo capsule (TXL) is a potential therapeutic agent for no-reflow. Thus, this study is aimed to investigate the pathogenesis of no-reflow in stroke, and whether TXL could alleviate no-reflow as well as its potential mechanisms of action. METHODS: Mice were orally administered with TXL (3.0 g/kg/d) after transient middle cerebral artery occlusion. We examined the following parameters: neurological function, no-reflow, leukocyte-endothelial cell interactions, HE staining, leukocyte subtypes, adhesion molecules, and chemokines. RESULTS: Our results showed stroke caused neurological deficits, neuron death, and no-reflow. Adherent and aggregated leukocytes obstructed microvessels as well as leukocyte infiltration in ischemic brain. Leukocyte subtypes changed after stroke mainly including neutrophils, lymphocytes, regulatory T cells, suppressor T cells, helper T type 1 (Th1) cells, Th2 cells, B cells, macrophages, natural killer cells, and dendritic cells. Stroke resulted in upregulated expression of adhesion molecules (P-selectin, E-selectin, and ICAM-1) and chemokines (CC-chemokine ligand (CCL)-2, CCL-3, CCL-4, CCL-5, and chemokine C-X-C ligand 1 (CXCL-1)). Notably, TXL improved neurological deficits, protected neurons, alleviated no-reflow and leukocyte-endothelial cell interactions, regulated multiple leukocyte subtypes, and inhibited the expression of various inflammatory mediators. CONCLUSION: Leukocyte-endothelial cell interactions mediated by multiple inflammatory factors are an important cause of no-reflow in stroke. Accordingly, TXL could alleviate no-reflow via suppressing the interactions through modulating various leukocyte subtypes and inhibiting the expression of multiple inflammatory mediators.

Efficacy and Safety of Different Courses of Tongxinluo Capsule as Adjuvant Therapy for Coronary Heart Disease after Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Tongxinluo capsule (TXLC) is a widely used traditional Chinese medicine for coronary heart disease (CHD). However, the efficacy and safety of different courses of TXLC for CHD after percutaneous coronary intervention (PCI) have not been systematically evaluated yet. The Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure, Wanfang Database, and Chinese Scientific Journal Database were searched from the inception to 26 August 2021. A meta-analysis was performed using a fixed- or random-effects model. The risk of adverse cardiovascular events, mortality, or adverse effects was evaluated by risk ratio (RR) with 95% confidence interval (CI). Thirty-four studies involving 3652 patients were finally included. After the 6-month treatment, compared with conventional treatment alone, TXLC combined with conventional treatment achieved better efficacy in lowering the risk of angiographic restenosis (RR = 0.37, 95% CI = 0.28−0.48, p < 0.001), myocardial infarction (RR = 0.38, 95% CI = 0.25−0.60, p < 0.001), heart failure (RR = 0.32, 95% CI = 0.18−0.56, p < 0.001), angina (RR = 0.26, 95% CI = 0.17−0.38, p < 0.001), revascularization (RR = 0.20, 95% CI = 0.09−0.46, p < 0.001), all-cause mortality (RR = 0.24, 95% CI = 0.10−0.58, p = 0.001), and mortality due to any cardiovascular event (RR = 0.27, 95% CI = 0.09−0.80, p = 0.018). After the 12-month treatment, TXLC reduced the recurrence risk of angina (RR = 0.40, 95% CI = 0.20−0.80, p = 0.009). However, there was no difference in any outcomes after the 3-month treatment. Besides, no difference was found in the incidence of adverse effects after the 3-month and 6-month treatments (3 months: RR = 0.73, 95% CI = 0.35−1.56, p = 0.418; 6 months: RR = 1.71, 95% CI = 0.74−3.93, p = 0.209). The certainty of evidence ranged from very low to moderate due to the risk of bias, inconsistency, and imprecision. TXLC showed beneficial effects on reducing the adverse cardiovascular events without compromising safety for CHD patients after PCI on the 6-month course. However, due to the unavoidable risk of bias, more high-quality and long-term studies are still needed to further evaluate the efficacy and safety of TXLC in many countries, not only in China.

Tongxinluo capsule as supplementation and cardiovascular endpoint events in patients with coronary heart disease: A systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials.

ETHNOPHARMACOLOGICAL RELEVANCE: Tongxinluo Capsule(TXLC) is a well-known traditional Chinese medicine prescription with effects of tonifying Qi and activating blood based on the Chinese herbal medicine theory that has been recommended as routine adjuvant treatment in patients with coronary heart disease (CHD) in China. AIM OF THE STUDY: This meta-analysis aimed to evaluate the efficacy and safety of TXLC as supplementation in the prevention of adverse cardiovascular events in patients with CHD. MATERIALS AND METHODS: We performed a literature search in Pubmed, Cochrane Library, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), Wan Fang Database, and Chinese Biomedical Database (CBM) from their inceptions to March 2020. Only randomized controlled trials (RCTs) that assessed supplementation with TXLC or placebo and with adverse cardiovascular outcomes, were included in this meta-analysis. Primary end points were myocardial infarction (MI), target vessel revascularization (TVR) or in-stent restenosis (ISR), and cardiovascular death. Secondary end points included cerebrovascular accidents, heart failure (HF), and unscheduled readmission for cardiovascular diseases (CVDs). Adverse drug events were also evaluated. Trial sequential analysis (TSA) was conducted to reduce random errors introduced by possible insufficient sample size. RESULTS: Eleven RCTs involving 1505 patients were analyzed. The mean(SD) age of included patients were 59.03(9.7) years. Treatment duration varied from 2 months to 12 months. Compared with placebo, TXLC supplementation showed significant effects on reducing the risk of MI (RR = 0.44, [95% CI, 0.24-0.80]), TVR or ISR (RR = 0.43, [95% CI, 0.31-0.58]), cerebrovascular accidents(RR = 0.17, [95% CI, 0.06-0.46]), HF (RR = 0.41, [95% CI, 0.21-0.79]), and unscheduled readmission for CVDs (RR = 0.72, [95% CI], P = 0.04), but did not have associations with incidence of cardiovascular death (RR = 0.53, [95% CI, 0.15-1.91]). Subgroups of trials with 2-month (MI: RR = 0.44, [95% CI, 0.13-1.53]; cardiovascular death: RR = 0.30, [95% CI, 0.01-7.67]; cerebrovascular accidents: RR = 0.04, [95% CI, 0.01-0.26]; unscheduled readmission for CVDs: RR = 0.43, [95% CI, 0.20-0.94]) and 12-month (MI: RR = 0.42, [95% CI, 0.20-0.89]; TVR or ISR: RR = 0.42, [95% CI, 0.31-0.58]; HF: RR = 0.34, [95% CI, 0.14-0.78]; unscheduled readmission for CVDs: RR = 0.85, [95% CI, 0.59-1.22]) intervention period were analyzed. The adverse drug reactions were mild with no significant difference between TXLC and placebo. CONCLUSIONS: This meta-analysis indicated that TXLC supplementation had beneficial effects on the prevention of cardiovascular adverse events, especially in TVR or ISR after coronary revascularization and may possibly lower the incidence of first or recurrent MI and HF within 12 months in patients with CHD, while insufficient sample size implied that these results lacked certain stability. And the effects of TXLC on cardiovascular mortality, cerebrovascular events, and unscheduled readmission for CVDs could not be confirmed due to insufficient cases. Clinical trials with large-sample sizes and extended follow-up time are of interest in the future researches.

Chinese medicine Tongxinluo capsule protects against blood-brain barrier disruption after ischemic stroke by inhibiting the low-density lipoprotein receptor-related protein 1 pathway in mice.

BACKGROUND: Chinese medicine Tongxinluo capsule (TXL) has been extensively used to treat ischemic stroke in China, and one of its mechanisms is to protect against blood brain barrier (BBB) disruption after stroke. However, the underlying protective mechanisms are not fully illuminated. It is reported that the low-density lipoprotein receptor-related protein 1 (LRP-1) is involved in BBB disruption after brain ischemia. In this study, we explored whether TXL could downregulate LRP-1 expression and subsequently protect against BBB disruption after stroke using permanent middle cerebral artery occlusion (pMCAO) in mice. METHODS: The animal model of ischemic stroke was induced by pMCAO in male adult C57BL/6J mice. The mice were orally administered TXL (3.0 g/kg) at 1, 3 and 21 h after pMCAO. Meanwhile, the LRP-1 antagonist receptor associated protein (RAP) was intracerebroventricularly injected at 1 and 21 h after stroke. We measured the following parameters at 6 and 24 h: LRP-1 protein level, BBB leakage, and the expression of tight junction (TJ) proteins including occludin, claudin-5 and zonula occludens-1 (ZO-1). RESULTS: Our results showed that TXL downregulated LRP-1 level, upregulated these TJ proteins level, and reduced BBB leakage in peri-infarct regions after pMCAO. Further study found that the inhibitor RAP played the same role as did TXL in upregulating these TJ proteins level and reducing BBB leakage after stroke. CONCLUSION: Our study demonstrates that TXL protects against BBB disruption after stroke via inhibiting the LRP-1 pathway.

Protective Effect of Tongxinluo Capsule on Cerebral Ischemia-reperfusion Injury and Its Mechanism of Action / 中国实验方剂学杂志

Objective:To study the protective effect of Tongxinluo capsule on cerebral ischemia-reperfusion injury, and explore the mechanism of Tongxinluo capsule in treating cerebral ischemia through network pharmacology. Method:The C57BL/6 mouse middle cerebral artery occlusion(MCAO) model was established by improved suture method and divided into sham operation group, model group, low, medium and high-dose Tongxinluo groups (crude drug 1,2,4 g·kg-1, intragastric administration), Aspirin group (2.055 g·L-1, intraperitoneal injection). Then, neurological function score and 2,3,5-triphenyltetrazole chloride(TTC) staining method were used to determine the infarct size of mice at 24, 48, 72 h by cerebral ischemia-reperfusion. First, chemical constituents of Tongxinluo capsule were screened from the BATMAN-TCM database, and the targets were analyzed. Then, gene ontology (GO) enrichment and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis were performed, and traditional Chinese medicine(TCM)-active ingredient-target network was constructed. Finally, the multi-dimensional pharmacological mechanism of Tongxinluo capsule in the treatment of cerebral ischemia was predicted. Result:Longa score, HE staining and TTC staining all suggested that Tongxinluo capsule could alleviate brain injury in mice after cerebral ischemia and reperfusion, and the improvement degree of Tongxinluo capsule on brain injury was gradually enhanced with the increase of Tongxinluo capsule dose. A total of 132 active components and 240 intersection targets, including cyclic adenosine monophosphate(cAMP)-dependent protein kinase catalytic subunit alpha (PRKACA), adenylate cyclase 1(ADCY1), serine/threonine kinase 1 (Akt1), dopamine receptor D2 (DRD2) and discs large homolog 4 (DLG4) were screened from 12 TCM in Tongxinluo capsule. GO was enriched in cationic channel activity, ion gated channel activity, gate channel activity, neurotransmitter receptor activity, ion channel activity, etc. KEGG was enriched in cAMP signaling pathway, calcium signaling pathway, neuroactive ligand-receptor interaction, cyclic guanosine monophosphate(cGMP)/protein kinase G(PKG) signaling pathway and dopaminergic synaptic signaling pathway. Conclusion:Tongxinluo capsule can alleviate brain damage in mice with cerebral ischemia-reperfusion, and achieve brain protection through multiple targets and multiple links. Network pharmacology reveals effective components，targets and pathway of Tongxinluo capsule in the treatment of cerebral ischemia, which provides theoretical support for the mechanism of Tongxinluo capsule in the treatment of cerebral ischemia.

The sonic hedgehog pathway mediates Tongxinluo capsule-induced protection against blood-brain barrier disruption after ischaemic stroke in mice.

Tongxinluo capsule (TXL), a Chinese prescription, has been extensively used for treating ischaemic cerebrovascular diseases in China. Studies have demonstrated that TXL protects the blood-brain barrier (BBB) after cerebral ischaemia. However, the underlying protective mechanisms are not fully elucidated. Enlightened by the critical role of sonic hedgehog (Shh) pathway in promoting BBB integrity through up-regulating tight junction (TJ) proteins, we examined whether the Shh pathway could mediate TXL-induced up-regulation of TJ proteins and subsequent protection against BBB disruption after stroke. Ischaemic stroke was induced in adult male C57BL/6J mice by permanent middle cerebral artery occlusion (pMCAO). The mice were orally administered TXL (3.0 g/kg) at 1, 3 and 21 hours after stroke. Meanwhile, cyclopamine, a specific Shh pathway inhibitor, was intraperitoneally injected at 1 and 21 hours after stroke. The following parameters were measured at 6 and 24 hours after pMCAO: BBB permeability; TJ proteins including occludin, claudin-5 and zonula occludens-1 (ZO-1); and Shh signalling molecules such as Shh, Patched, Smoothened (Smo) and Gli-1. Our results showed that TXL protected against BBB disruption at 6 and 24 hours after pMCAO, and cyclopamine partly reversed the protective effect of TXL on BBB. Meanwhile, cyclopamine blocked the effect of TXL-up-regulated expression of occludin, claudin-5 and ZO-1. Moreover, TXL up-regulated the expression of Shh derived from astrocytes, Patched, Smo and Gli-1, and thus activated the Shh pathway. And cyclopamine inhibited TXL-induced activation of the Shh pathway. Thus, our study demonstrates that the Shh pathway mediates TXL-induced protection against BBB disruption after ischaemic stroke.

Tongxinluo Capsule () for Cardiac Syndrome X: A Systematic Review and Meta-Analysis.

OBJECTIVE: To evaluate the efficacy and safety of Tongxinluo Capsule (, TXL) for patients with cardiac syndrome X (CSX). METHODS: Randomized controlled trials (RCTs) regarding TXL in the treatment of CSX were searched in Chinese Biomedicine Literature Database, China National Knowledge Infrastructure, Chinese Scientific Journal Database, Wanfang Database, PubMed, EMBASE, Cochrane Central Register of Controlled Trial, websites of the Chinese and International Clinical Trial Registry platform up to June 30, 2015. The intervention was either TXL alone or TXL combined with conventional treatment, while the control intervention was conventional treatment with or without placebo. Data extraction, methodological quality assessment and data analyses were performed according to the Cochrane criteria. The primary outcome was a composite event of death, acute myocardial infarction (AMI), angina requiring hospitalization, revascularization, and heart failure. The secondary outcome measures were angina symptom improvement, electrocardiograph (ECG) improvement, and serum endothelin-1 (ET-1) level. The adverse events were also recorded. RevMan 5.3 software was applied for data analyses. RESULTS: Twelve RCTs (696 patients) were included. Compared with conventional treatment, the addition of TXL to conventional treatment showed some benefits on relieving angina symptoms [risk ratio (RR): 1.46, 95% confidence interval (CI) (1.25, 1.71), P<0.01], and improving ECG [RR: 1.45, 95% CI (1.21, 1.74), P<0.01]. The pooled result did not support a benefit of TXL on reducing the incidence of primary outcome [RR: 0.20, 95% CI (0.02, 1.61), P=0.13]. In addition, TXL decreased serum ET-1 concentration of CSX patients [standardized mean number:-1.63, 95% CI (-2.29,-0.96), P<0.01]. No serious adverse events were reported. CONCLUSIONS: TXL documents potential benefits on attenuating angina symptoms, improving ECG and decreasing serum ET-1 level for CSX patients. However, more rigorous RCTs with high quality are needed to confirm its efficacy and safety.

Tongxinluo Capsule () for Cardiac Syndrome X: A Systematic Review and Meta-Analysis / 中国结合医学杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy and safety of Tongxinluo Capsule (, TXL) for patients with cardiac syndrome X (CSX).</p><p><b>METHODS</b>Randomized controlled trials (RCTs) regarding TXL in the treatment of CSX were searched in Chinese Biomedicine Literature Database, China National Knowledge Infrastructure, Chinese Scientific Journal Database, Wanfang Database, PubMed, EMBASE, Cochrane Central Register of Controlled Trial, websites of the Chinese and International Clinical Trial Registry platform up to June 30, 2015. The intervention was either TXL alone or TXL combined with conventional treatment, while the control intervention was conventional treatment with or without placebo. Data extraction, methodological quality assessment and data analyses were performed according to the Cochrane criteria. The primary outcome was a composite event of death, acute myocardial infarction (AMI), angina requiring hospitalization, revascularization, and heart failure. The secondary outcome measures were angina symptom improvement, electrocardiograph (ECG) improvement, and serum endothelin-1 (ET-1) level. The adverse events were also recorded. RevMan 5.3 software was applied for data analyses.</p><p><b>RESULTS</b>Twelve RCTs (696 patients) were included. Compared with conventional treatment, the addition of TXL to conventional treatment showed some benefits on relieving angina symptoms [risk ratio (RR): 1.46, 95% confidence interval (CI) (1.25, 1.71), P<0.01], and improving ECG [RR: 1.45, 95% CI (1.21, 1.74), P<0.01]. The pooled result did not support a benefit of TXL on reducing the incidence of primary outcome [RR: 0.20, 95% CI (0.02, 1.61), P=0.13]. In addition, TXL decreased serum ET-1 concentration of CSX patients [standardized mean number:-1.63, 95% CI (-2.29,-0.96), P<0.01]. No serious adverse events were reported.</p><p><b>CONCLUSIONS</b>TXL documents potential benefits on attenuating angina symptoms, improving ECG and decreasing serum ET-1 level for CSX patients. However, more rigorous RCTs with high quality are needed to confirm its efficacy and safety.</p>

Protective effects of Tongxinluo on cerebral ischemia/reperfusion injury related to Connexin 43/Calpain II/Bax/Caspase-3 pathway in rat.

ETHNOPHARMACOLOGICAL RELEVANCE: Tongxinluo (TXL) is a multifunctional traditional Chinese medicine and has been widely used in the treatment of cardiovascular and cerebrovascular diseases. Numerous studies demonstrate that TXL is a novel neuroprotective drug, however, the mechanisms are largely unknown. AIM OF THE STUDY: we aimed to demonstrate the protective effect of TXL on cerebral ischemia/reperfusion (I/R) injury and provide the evidence for the involvement of Connexin 43/Calpain II/ Bax/Caspase-3 pathway in TXL-mediated neuroprotection. METHODS: Focal cerebral I/R injury were induced by transient middle cerebral artery occlusion (MCAO, for 90min) in adult male Sprague-Dawley rats. We estimated the effects of TXL on I/R injury including neurological deficit assessment and cerebral infarct volume measurement via TTC staining, and detected the protein expression of Connexin 43 (Cx43) by western blot. Furthermore, after the intracerebroventricular injection of carbenoxolone (CBX, the inhibitor of Cx43) at 30min before MCAO surgery, Calpain II, Bax and cleaved Caspased-3 immunoreactivity in ischemic penumbra region was detected by immunofluorescent staining, and cell apoptosis was detected by TUNEL staining. RESULTS: TXL treatment greatly improved neurological deficit and reduced the infarction volume compared to MCAO with buffer treatment (P<0.05), and TXL pre-post treatment showed better results than TXL pre-treatment. TXL pre-post treatment significantly up-regulated Cx43 protein expression at 3d, 7d and 14d post-injury compared to MCAO with buffer treatment (P<0.05). Meanwhile, the immunoreactivity of Calpain II, Bax and cleaved Caspase-3 in ischemic penumbra region was obviously decreased by TXL pre-post treatment compared to MCAO group (P<0.05). However, with the treatment of the Cx43 inhibitor, CBX, the down-regulated effect of TXL on Calpain II, Bax and cleaved Caspase-3 immunoreactivity was abolished (P<0.05). Moreover, the protective effect of TXL against neuron apoptosis in penumbra region was conteracted by CBX (P<0.05). CONCLUSIONS: TXL could effectively protect against I/R injury and reduced cell death via Cx43/Calpain II/Bax/Caspase-3 pathway, which contribute to I/R injury prevention and therapy.

Neuroprotective effect of the traditional Chinese herbal formula Tongxinluo: a PET imaging study in rats.

Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography (PET) studies on the neuroprotective effect of Tongxinluo on cerebral ischemia/reperfusion in small animals. In the present study, Tongxinluo superfine powder suspension or its vehicle was administered intragastrically to rats for 5 successive days before middle cerebral artery occlusion. (18)F-fluorodeoxyglucose (FDG) small animal PET imaging showed that at 1 and 2 weeks after cerebral ischemia/reperfusion, glucose metabolism in the ischemic area was greater in rats that had received Tongxinluo than in those that had received the vehicle. Nissl staining showed that 2 weeks after cerebral ischemia/reperfusion, there was less neuronal loss in the prefrontal cortex in Tongxinluo-treated rats than in controls. In addition, Tongxinluo-treated animals showed better neurologic function and lower cerebral infarct volume than rats that received the vehicle. These findings suggest that Tongxinluo exhibits neuroprotective effects in cerebral ischemia/reperfusion injury and demonstrates that (18)F-FDG small animal PET imaging is a useful tool with which to study the molecular pharmacology of traditional Chinese medicine.