Efficacy of tanshinone IIA in rat models with myocardial ischemia–reperfusion injury: a systematic mini-review and meta-analysis

Introduction

According to the World Health Organization, ischemic heart disease remains the primary cause of death worldwide, accounting for 16% of all deaths (Wang et al., 2022). As the world’s population ages, the incidence of acute myocardial infarction rises annually (Reynolds et al., 2017). Therapies for acute myocardial infarction significantly impact the global population’s economic burdens (Pasala et al., 2022). The prompt restoration of coronary blood supply is the most effective method for preventing myocardial cell death caused by myocardial ischemic injury. This is achieved primarily through percutaneous coronary intervention, coronary artery bypass grafting operations, and thrombolytic technology (Biscaglia et al., 2022).

Myocardial ischemia–reperfusion injury (MIRI) is a secondary complication of ischemic heart disease. It occurs when blood flow is suddenly restored to the ischemic myocardium, potentially resulting in cardiac myocyte dysfunction, structural damage to cardiac cells, and cell death, all of which contribute to the deterioration of cardiac function (Evans et al., 2020; Liu et al., 2018). The cellular and molecular events involved in MIRI are complex and mediated through multiple pathways, including oxygen free radicals, energy metabolism disruption, calcium overload, autophagy, apoptosis, mitochondrial dysfunction, and microvascular injury (Chen et al., 2023; He et al., 2022). The exact mechanism of MIRI remains incompletely understood, and there is currently no comprehensive treatment available for it.

Tanshinone IIA is a lipid-soluble diterpenoid isolated from the traditional Chinese medicine Salvia miltiorrhiza Bunge (Huang et al., 2022). Owing to its anti-inflammatory, lipid-regulating, antioxidant, and anti-apoptotic effects, tanshinone IIA can prevent various cardiovascular disorders (Li, Xu & Liu, 2018). Consequently, it is commonly used in the treatment of cardiovascular diseases (Ren et al., 2019).

MIRI can impact markers such as oxidative stress and the extent of myocardial infarction. The size of the myocardial infarction area directly correlates with the severity of MIRI. During ischemia, reactive oxygen species and reactive nitrogen species, such as superoxide anions and nitric oxide, are overproduced, disrupting redox balance and leading to oxidative stress (Chen, Shi & Guo, 2021). Superoxide dismutase (SOD) and malondialdehyde (MDA) are crucial markers of oxidative stress (Tian et al., 2019).

In this study, an extensive literature review on the intervention of tanshinone IIA in MIRI rats was conducted. The therapeutic effects of tanshinone IIA were systematically evaluated in rat models with MIRI, to provide medical evidence for the clinical application of tanshinone IIA.

Materials and Methods

Results

Study selection

Based on the specified article search strategy, 295 articles were initially identified. Using EndNote X9 software, 90 duplicates were removed. Subsequently, after the review of titles and abstracts, 153 articles were excluded. Upon full-text review, an additional 37 articles were eliminated. Ultimately, 15 articles were included in the meta-analysis (Fig. 1).

Quality evaluation

The SYRCLE’s risk of bias tool was used to assess bias risk in 15 articles. Tang et al. (2017) detailed the randomization method, while others mentioned randomization without specifying the method. Both the experimental and control groups had similar baseline characteristics. Each study reported its findings clearly and comprehensively. None of the studies indicated any other biases, so they were all classified as “low risk”. However, none of the studies provided information on allocation concealment, random housing of animals during the experiment, blinding of caregivers or investigators, random outcome assessment, or blinding of outcome assessment, resulting in all studies being categorized as “unclear” (Fig. 2). Overall, the included articles were not of particularly high quality. There are notable flaws in the design and implementation of animal experimental methodology in these studies that need to be addressed to facilitate the translation of basic research into clinically feasible investigations.

Meta-analysis of primary outcomes

Superoxide dismutase

Nine of the included studies (Ding, Wang & Huang, 2020; Tang et al., 2017; Jiao, 2016; Hu et al., 2015; Dai et al., 2013; Fu et al., 2007; Wei et al., 2014; Shen et al., 2018; Zhai et al., 2024) examined the effect of tanshinone IIA on SOD levels (unit: U/mol) in rat models with MIRI (experimental group, n = 192; control group, n = 85). Owing to significant heterogeneity among the articles (p < 0.00001, I² = 99%), we conducted subgroup analyses to explore the sources of this heterogeneity. Subgroups were categorized based on ischemia duration (15 min ≤ time < 30 min, 30 min ≤ time < 40 min, or 40 min ≤ time ≤ 45 min), reperfusion duration (30 min ≤ time < 120 min, 120 min ≤ time < 180 min, or 180 min ≤ time ≤ 480 min), dosage (5 mg kg⁻¹ d⁻¹ ≤ dosage < 20 mg kg⁻¹ d⁻¹, 20 mg kg⁻¹ d⁻¹ ≤ dosage < 30 mg kg⁻¹ d⁻¹, or 30 mg kg⁻¹ d⁻¹ ≤ dosage ≤ 60 mg kg⁻¹ d⁻¹), route of administration (i.v., i.g., or i.p.), and timing of treatment (prior to ischemia, after ischemia and before reperfusion, after reperfusion, prior to ischemia and after reperfusion). The results indicated significantly lower heterogeneity in the subgroup with an ischemic duration of 40–45 min (Table 2) (Figs. S1–S5), suggesting that this factor might be contributing to the heterogeneity. However, substantial heterogeneity persisted in the other subgroups (Table 2) (Figs. S1–S5), indicating that other factors could also be influencing the heterogeneity. SOD levels can be influenced by various factors. Differences in testing instruments and methodologies used across various studies may have been a primary contributing factor. Additionally, regional variations in the technique of left anterior descending coronary artery ligation for inducing ischemia and reperfusion during the modeling process could also be responsible. Apart from these factors, no other significant methodological differences were identified among the nine studies. Therefore, a random-effects model was utilized to combine data from the nine studies. According to this meta-analysis, the tanshinone IIA group demonstrated a significant increase in SOD levels compared with the control group (MD = 5.25, 95% CI [4.27–6.23], p < 0.00001) (Fig. 3).

Table 2:

Subgroup analysis of SOD based on ischemia duration, reperfusion duration, dosage, route and treatment time.

Criteria for grouping	Subgroup	n	Mean difference (MD)	I2 (%)	Z	P
Ischemia duration	15 min ≤ Time < 30 min	3	48.32 (21.61, 75.03)	85	3.55	0.0004
	30 min ≤ Time < 40 min	11	3.94 (2.97, 4.92)	99	7.92	<0.00001
	40 min ≤ Time ≤ 45 min	6	13.60 (9.90, 17.31)	26	7.19	<0.00001
Reperfusion duration	30 min ≤ Time < 120 min	3	48.32 (21.61, 75.03)	85	3.55	0.0004
	120 min ≤ Time < 180 min	8	16.05 (10.20, 21.90)	83	5.38	<0.00001
	Time ≥ 180 min	9	2.19 (1.32, 3.05)	99	4.96	<0.00001
Dosage	5 mg kg−1 d−1≤ Dosage < 20 mg kg−1 d−1	14	4.43 (3.46, 5.40)	99	8.93	<0.00001
	20 mg kg−1 d−1≤ Dosage < 30 mg kg−1 d−1	1	44.94 (23.48, 66.40)	—	4.11	<0.0001
	30 mg kg−1 d−1≤ Dosage ≤ 60 mg kg−1 d−1	5	23.11 (8.75, 37.46)	92	3.15	0.002
Route	i.v	1	15.30 (2.34, 28.26)	—	2.31	0.02
	i.g	5	15.89 (8.28, 23.49)	89	4.09	<0.0001
	i.p	14	2.78 (1.87, 3.68)	99	6.02	<0.00001
Treatment time	Prior to ischemia After ischemia and before reperfusion After reperfusion Prior to ischemia and after reperfusion	12 1 6 1	20.70 (13.92, 27.48) 2.48 (2.28, 2.68) 1.71 (0.82, 2.61) 112.39 (96.00, 128.87)	89 — 99 —	5.98 23.74 3.76 13.44	<0.00001 <0.00001 0.0002 <0.00001

DOI: 10.7717/peerj.17885/table-2

Methane dicarboxylic aldehyde

Eight studies (Jiao, 2016; Hu et al., 2015; Zhang & Zhang, 2010; Yang, 2010; Fu et al., 2007; Wei et al., 2014; Shen et al., 2018; Zhai et al., 2024) examined the effect of tanshinone IIA on MDA levels (unit: nmol/mL) following intervention in rat models with MIRI (experimental group, n = 192; control group, n = 82). Owing to significant result heterogeneity (p < 0.00001, I² = 1.0%), a subgroup analysis was conducted to identify the sources of heterogeneity based on ischemia duration (15 min ≤ time < 30 min, 30 min ≤ time < 40 min, or 40 min ≤ time ≤ 45 min), reperfusion duration (30 min ≤ time < 120 min, 120 min ≤ time < 180 min, or 180 min ≤ time ≤ 480 min), dosage (5 mg kg⁻¹ d⁻¹ ≤ dosage < 20 mg kg⁻¹ d⁻¹, 20 mg kg⁻¹ d⁻¹ ≤ dosage <30 mg kg⁻¹ d⁻¹, or 30 mg kg⁻¹ d⁻¹ ≤ dosage ≤ 60 mg kg⁻¹ d⁻¹), route of administration (i.v., i.g., or i.p.), and treatment timing (prior to ischemia, after ischemia and before reperfusion, after reperfusion, prior to ischemia and after reperfusion). The results indicated a reduction in heterogeneity in the subgroup with dosages of 30–60 mg/kg (Table 3) (Figs. S6–S10), suggesting that dosage contributed to the observed heterogeneity. However, significant heterogeneity persisted in the other subgroups (Table 3) (Figs. S6–S10), suggesting that the heterogeneity had other causes. Variations in the test kit employed and the location of the ligated left anterior descending coronary artery among studies possibly contributed to the observed heterogeneity. We employed a random-effects model. The meta-analysis showed that the tanshinone IIA group significantly reduced MDA levels compared with the control group (MD = −1.48, 95% CI [−1.82 to −1.14], p < 0.00001) (Fig. 4).

Table 3:

Subgroup analysis of MDA based on ischemia duration, reperfusion duration, dosage, route and treatment time.

Criteria for grouping	Subgroup	n	Mean difference (MD)	I2 (%)	Z	P
Ischemia duration	15 min ≤ Time < 30 min	6	−1.59 (−2.48, −0.70)	99	3.49	0.0005
	30 min ≤ Time < 40 min	10	−0.96 (−1.20, −0.72)	98	7.85	<0.00001
	40 min ≤ Time ≤ 45 min	4	−0.82 (−1.77, 0.12)	92	1.70	0.09
Reperfusion duration	30 min ≤ Time < 120 min	6	−1.59 (−2.48, −0.70)	99	3.49	0.0005
	120 min ≤ Time < 180 min	6	−1.04 (−1.91, −0.17)	98	2.34	0.02
	Time ≥ 180 min	8	−0.84 (−1.09, −0.59)	98	6.54	<0.00001
Dosage	5 mg kg−1 d−1≤ Dosage < 20 mg kg−1 d−1	15	−0.91 (−1.22, −0.60)	100	5.78	<0.00001
	20 mg kg−1 d−1≤ Dosage < 30 mg kg−1 d−1	2	−2.37 (−3.92, −0.81)	96	2.98	0.003
	30 mg kg−1 d−1≤ Dosage ≤ 60 mg kg−1 d−1	3	−1.65 (−2.38, −0.92)	72	4.44	<0.00001
Route	i.v	9	−1.32 (−2.12, −0.51)	100	3.20	0.001
	i.g	11	−0.93 (−1.16, −0.70)	98	7.92	<0.00001
Treatment time	Prior to ischemia After ischemia and before reperfusion After reperfusio Prior to ischemia and after reperfusion	12 1 6 1	−1.31 (−2.01, −0.620 −0.71 (−0.77, −0.65) −0.59 (−0.89, −0.30) −3.52 (−4.10, −2.94)	100 — 99 —	3.69 22.45 3.93 11.94	0.0002 <0.00001 <0.0001 <0.00001

DOI: 10.7717/peerj.17885/table-3

Meta-analysis of secondary outcomes

Myocardial infarction area

Ten of the included studies (Ding, Wang & Huang, 2020; Ma et al., 2017; Li et al., 2016; Hu et al., 2015; Yuan et al., 2014; Yang, 2010; Wei et al., 2014; Shen et al., 2018; Zhai et al., 2024; Li et al., 2022) investigated the effect of tanshinone IIA on myocardial infarction area in rat models with MIRI (experimental group, n = 249; control group, n = 107). Units: %. We conducted a subgroup analysis to identify the sources of heterogeneity based on ischemia duration (15 min ≤ time < 30 min, 30 min ≤ time < 40 min, or 40 min ≤ time ≤ 45 min), reperfusion duration (30 min ≤ time < 120 min, 120 min ≤ time < 180 min, or 180 min ≤ time ≤ 480 min), dosage (5 mg kg⁻¹ d⁻¹ ≤ dosage < 20 mg kg⁻¹ d⁻¹, 20 mg kg⁻¹ d⁻¹ ≤ dosage < 30 mg kg⁻¹ d⁻¹, or 30 mg kg⁻¹ d⁻¹ ≤ dosage ≤ 60 mg kg⁻¹ d⁻¹), route of administration (i.v., i.g., or i.p.), and treatment timing (prior to ischemia, after ischemia and before reperfusion, after reperfusion, prior to ischemia and after reperfusion), considering the significant heterogeneity in the results (p < 0.00001, I² = 98%). The results indicated lower heterogeneity in the group with ischemia duration of 40–45 min compared with other groups (Table 4) (Figs. S9–S12), suggesting that ischemia duration was a source of heterogeneity. However, substantial heterogeneity persisted in the remaining subgroups (Table 4) (Figs. S9–S12), suggesting that additional sources of heterogeneity existed. A random-effects model was employed. The tanshinone IIA group significantly reduced myocardial infarction area compared with the control group (MD = −15.74, 95% CI [−19.27 to −12.21], p < 0.00001) (Fig. 5).

Table 4:

Subgroup analysis of myocardial infarction area based on ischemia duration, reperfusion duration, dosage, route and treatment time.

Criteria for grouping	Subgroup	n	Mean difference (MD)	I2 (%)	Z	P
Ischemia duration	15 min ≤ Time < 30 min	6	−6.51 (−10.75, −2.26)	96	3.00	0.003
	30 min ≤ Time < 40 min	15	−21.29 (−24.62, −17.97)	96	12.55	<0.00001
	40min ≤ Time ≤ 45 min	3	−9.68 (−16.05, −3.31)	92	2.98	0.003
Reperfusion duration	30 min ≤ Time < 120 min	6	−6.51 (−10.75, −2.26)	96	3.00	0.003
	120 min ≤ Time < 180 min	9	−14.21 (−18.33, −10.09)	97	6.76	<0.00001
	180 min ≤ Time ≤ 480 min	9	−23.63 (−29.29, −17.98)	96	8.19	<0.00001
Dosage	5 mg kg−1 d−1≤ Dosage < 20 mg kg−1 d−1	18	−16.61 (−21.30, −11.92)	98	6.94	<0.00001
	20 mg kg−1 d−1≤ Dosage < 30 mg kg−1 d−1	5	−13.42 (−18.33, −8.51)	96	5.36	<0.00001
	30 mg kg−1 d−1≤ Dosage ≤ 60 mg kg−1 d−1	1	−12.35 (−14.66, −10.04)	—	10.47	<0.00001
Route	i.v	5	−15.69 (−20.34, −11.05)	94	6.62	<0.00001
	i.g	6	−11.31 (−18.12, −4.51)	99	3.26	0.001
	i.p	13	−17.89 (−24.06, −11.72)	98	5.68	<0.00001
Treatment time	Prior to ischemia After ischemia and before reperfusion After reperfusio Prior to ischemia and after reperfusion	16 1 6 1	−11.09 (−14.74, −7.44) −30.27 (−33.69, −26.85) −25.23 (−31.53, −18.92) −20.19 (−23.80, −16.58)	98 — 95 —	5.95 17.34 7.84 10.97	<0.00001 <0.00001 <0.00001 <0.00001

DOI: 10.7717/peerj.17885/table-4

Publication bias analysis

Publication bias in the meta-analysis of SOD, MDA, and myocardial infarction area was assessed using Egger’s test and funnel plots. The results showed asymmetry in the funnel plots and Egger’s tests for each SOD, MDA, and myocardial infarction area, indicating potential publication bias. This bias could be influenced by factors such as the overall poor quality of the included articles (Fig. 6).

Sensitivity analysis

To assess the consistency and reliability of the meta-analysis results, sensitivity analyses were conducted for SOD, MDA, and myocardial infarction area outcomes included in this study. Each meta-analysis was systematically recalculated after the exclusion of one study at a time, and the results were combined for the remaining studies. The sensitivity analysis indicated that excluding individual studies did not significantly alter the combined effect sizes for SOD, MDA, and myocardial infarction area. This underscores the robustness of the conclusions drawn from this meta-analysis (Fig. 7).

Discussion

This systematic review and meta-analysis investigated the efficacy and utility of tanshinone IIA in treating MIRI in rat studies, aiming to identify success factors and provide robust evidence for future treatments of MIRI. The left anterior descending coronary artery was consistently used as the site for ligation and release in the rat models of MIRI included in this systematic review and meta-analysis, ensuring the validity and reliability of the data input and minimizing bias. SOD serves as the primary oxygen radical scavenging enzyme in organisms, while MDA is a critical indicator of the severity of free radical injury. In MIRI, disruption of cellular oxidative stress equilibrium occurs, and both SOD and MDA levels serve as markers of this imbalance in the body (Zhang et al., 2022). The myocardial infarction area directly reflects the severity of MIRI. Therefore, we conducted a systematic review and meta-analysis to compile data on tanshinone IIA therapy in rat models of MIRI.

Oxidative stress plays a crucial role in the pathogenesis of myocardial injury. During myocardial ischemia and hypoxia, significant amounts of oxygen radicals are generated, leading to increased permeability of cardiac cell membranes and potential necrosis (Petrosillo et al., 2005). SOD neutralizes free radicals and suppresses the formation of highly reactive hydroxyl radicals (Fujii, Homma & Osaki, 2022). Elevated SOD levels enhance the body’s antioxidant capacity, thereby mitigating myocardial injury. Consequently, SOD was selected as one of the primary endpoints. The findings showed that tanshinone IIA treatment in rat models with MIRI resulted in increased serum SOD levels. Similar outcomes were observed across subgroups based on ischemia duration, reperfusion duration, dosage, route, and treatment time. Furthermore, we identified ischemia duration as a potential source of heterogeneity and noted that subgroup analysis only partially reduced this heterogeneity. This heterogeneity is attributable to factors such as measurement discrepancies between research institutions and variations in the site of ligation of the left anterior descending coronary artery during the experiments.

MDA is the end product of lipid peroxidation by oxygen radicals. MDA can induce cell membrane degeneration and alter membrane fluidity and permeability, thereby indicating the extent of oxidative damage to cardiac myocytes (Nehra et al., 2022; Tawfik, Makary & Keshawy, 2021). SOD serves as an indicator of the body’s antioxidant capacity, while MDA levels reflect the presence of free radicals. Therefore, MDA was selected as one of the primary outcomes of this study. The results demonstrated that tanshinone IIA reduced MDA levels in the serum of rat models with MIRI, with consistent findings across subgroups based on reperfusion duration, dosage, route, and treatment time. However, subgroup analysis revealed that tanshinone IIA did not significantly reduce MDA levels in the subgroup with ischemia duration between 40 and 45 min (MD = −0.82, 95% CI [−1.77–0.12], p = 0.09). These results suggest that tanshinone IIA was less effective in mitigating MIRI under conditions of longer ischemic durations. However, the subgroup comprised only four studies, necessitating further research to validate this conclusion. Despite the reduction in subgroup heterogeneity achieved through subgroup analysis, significant heterogeneity persisted in other subgroups. Differences in measurement techniques across studies and variations in the site of ligation of the left anterior descending coronary artery possibly contributed to this heterogeneity.

The myocardial infarction area serves as a direct measure of MIRI severity and visually depicts the therapeutic impact of tanshinone IIA. The results showed that tanshinone IIA reduced the myocardial infarction area in rat models with MIRI, with consistent findings across subgroups based on ischemia duration, reperfusion duration, dosage, route, and treatment time. Moreover, we identified ischemia duration as a potential source of heterogeneity. However, there remained unexplained variation, which is attributable to differences in detection equipment and methodologies used across studies.

This systematic review represents the first comprehensive examination of the effects of tanshinone IIA on rat models with MIRI. The included articles underwent rigorous filtering and inspection processes. It can be inferred that the overall quality of the included articles was not particularly high. Despite the rigorous evaluation of the tanshinone IIA intervention in rat models with MIRI, this study had several limitations: First, only articles written in Chinese and English were included. The search for grey articles and conference articles was inadequate owing to challenges in accessing these sources. Second, some results exhibited high heterogeneity, with a few included publications and outcome indicators demonstrating publication bias. Third, this article represents a meta-analysis of animal experiments, which may have been influenced by the quality of the original study design, resulting in a lower quality overall and potentially affecting the accuracy of the results. This study was limited to rat models with left anterior descending coronary artery ligation to induce ischemia and reperfusion. All studies included were conducted in China, with no representation from other geographical regions, which constitutes a limitation in the scope of the research. Fourth, the included studies lacked descriptions regarding allocation concealment, blinding of caregivers and investigators, random housing, and blinding of outcome assessment. Furthermore, this meta-analysis was limited to 15 articles, of which seven were in English and eight in Chinese, with a greater number of Chinese articles than English articles, suggesting a potential language bias. Consequently, the included studies were categorized as having uncertain risks. To enhance the validity of the study’s conclusions, larger sample sizes and higher-quality studies are necessary.

Conclusion

In this meta-analysis, 15 articles were included to provide more reliable preclinical evidence concerning SOD, MDA, and myocardial infarction area. A comprehensive analysis of tanshinone IIA use in rat models with MIRI revealed significant efficacy when the ischemia duration was less than 40 min. Tanshinone IIA demonstrated a notable therapeutic effect through intraperitoneal, intragastric, and intravenous administrations at doses exceeding 5 mg/kg. Additionally, treatment with tanshinone IIA at all stages—prior to myocardial ischemia, after ischemia but before reperfusion, prior to ischemia and after reperfusion, and after reperfusion—showed satisfactory results. Therefore, the potential translation of tanshinone IIA from laboratory research to clinical treatment for MIRI holds considerable promise.

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