Pachypodol attenuates arsenic triggered cardiac damage via rectifying oxidative stress, inflammation, apoptosis and histopathological alterations

1 Introduction

Arsenic is a well-known heavy metal which is ubiquitously present in our surroundings and considered as a major health concern across the globe. It is documented that arsenic leaches into drinking water through various sources such as bedrocks and earth crust (Vahter, 2008). Humans as well as other animals are exposed toarsenic via contaminated food and water, air as well as seafood (mussels, prawns, oyster, fish) (McCarty et al., 2011). It is reported that high concentrations of arsenic are present in urine, hoof, hair as well as nails (Roy et al., 2008). Furthermore, workers at chemical factories, mining sites and smelters are exposed to high concentration of arsenic. It is estimated that arsenic concentrations vary from one place to another such as the areas of low anthropogenic activities have 1–3 ng/m³ while industrial zones have 20–30 ng/m³ (ATSDR, 2000). Owing to high rate of absorption, slow elimination as well as small particle size, arsenic adversely affect various organs of body (Bergin et al., 2016).

It is revealed that arsenic exposure damages various body organs including skin, liver, lungs, heart, and urinary bladder (States et al., 2009; Moon et al., 2012). Various epidemiological investigations elucidated a strong relationship between arsenic contaminated water and cardiovascular disorders (Sanchez-Soria et al., 2012). Chowdhury and Daalen (2019) revealed that chronic exposure to arsenic instigates different cardiac impairments such as ischemia, arrhythmia as well as heart failure. It is reported that myocardial oxidative stress & apoptosis are primary factors underlying the arsenic instigated cardiac damages (Jiang et al., 2021). Furthermore, a long-term arsenic intoxication escalates the systolic blood pressure, total cholesterol, AST, bilirubin, creatinine, urea as well as reduces the levels of high-density lipoproteins (HDL) which ultimately instigate hypertension (Balarastaghi et al., 2022).

However, the management of arsenic induced toxicities is still complicated owing to lack of efficient treatment (Flora, 2020). Natural compounds are widely used as adjuvant therapy to treat various disorders (Men et al., 2022; Aboubakr et al., 2023). It is reported that plant-based flavonoids have potential to bind with heavy metals owing to their antioxidative abilities (Tay et al., 2013). PCHP is a plant derived flavonoid which demonstrated various pharmacological potentials including anti-microbial, cytoprotective, anti-apoptotic as well as anti-oxidative (Kim et al., 2019; Krithika et al., 2021; Zhang et al., 2021; Kim et al., 2019). Therefore, this investigation was executed to investigate the attenuative potential of PHCP to rectify arsenic provoked cardiac toxicity in rats.

2 Materials and methods

3 Results

3.6

3.6 Impact of PCHP on histology

Arsenic intoxication instigated inflammation, degeneration of endocardium, cardiac edema, as well as abnormal shape of cardiomyocytes in contrast to control group. However, PCHP + arsenic treatment remarkably (p < 0. 05) restored aforementioned histopathological impairments. Nonetheless, control and PCHP alone treated group showed normal histology of cardiac tissues (Fig. 1).

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Fig. 1

Histopathological analysis of heart tissues. H&E stain; 40X (A) Control group exhibited normal architecture of heart tissues (B) Arsenic exposed group demonstrated fibrosis, inflammation as well as large interstitial spaces (edema) (C) Arsenic + PCHP group showed a remarkable recovery in contrast to Arsenic exposed group (D) Only PCHP supplemented group showed normal morphology of cardiac tissues as in control group.

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4 Discussion

Our findings demonstrated that arsenic intoxication reduced the antioxidant enzyme’s concentration (CAT, GPx, SOD, GSR & GSH) while downregulating the levels of ROS & MDA. Antioxidant enzymes are primary barriers against oxidative damage (Berroukeche et al., 2022). Various studies showed a strong association between ROS and arsenic instigated cellular damages (Liu and Jan, 2000). The overproduction of ROS retards the levels of these enzymes and disrupts the normal architecture of cells which ultimately leads to the progression of various pathologies (Mukherjee et al., 2015). Moreover, excessive production of free radicals decreases the activities of antixodiant enzymes which ultimately impairs the endogenous cellular defense system (Ahmad et al., 2023). It is reported that arsenic reduces the activities of SOD along with CAT via decreasing the availability of NADH while escalating the levels of superoxide anions (Das et al., 2010). Our results matched with the investigations of Ijaz et al. (2023) who elucidated that administration of arsenic reduced these enzyme’s concentration while escalating the levels of lipid peroxidation. Plant-based flavonoid has potential to increase the activities of antioxidant enzymes (Ijaz et al., 2022). However, co-treatment of PCHP remarkably reduced antioxidant enzymes activities via regulating the levels of ROS owing to its ROS scavenging abilities.

Our investigation manifested that arsenic exposure augmented the levels of CK-MB, LHD, CPK as well as troponin-1 in cardiac tissues of rats. Abovementioned cardiac biomarkers are primary indicators of cardiac injury therefore, elevated levels of these biomarkers in the bloodstream indicate severe cardiac damage (Warings et al., 2000). Our findings are corroborated by the previous investigation which elucidated that arsenic administration triggers various alterations in cardiac tissues which are characterized by escalated levels of abovementioned cardiac injury markers (Jalaludeen et al., 2015). Nonetheless, the supplementation of PCHP reduced the levels of these biomarkers which demonstrates its cardioprotective potential.

Our findings demonstrated that the administration of arsenic culminated in an increase in the concentration of inflammatory biomarkers (IL-1β, TNF-α, IL-6, NF-κB & COX-2 activity). NF-κB is a principal biomarker contributing substantially to the augmentation of the aforementioned proinflammatory biomarkers, ultimately leading to the onset of acute inflammation and the subsequent damages associated with ROS (Zha et al., 2014). Furthermore, COX-2 serves as a substantial mediator that prompts the incipience of inflammatory cascade in the cardiac tissues (Gilroy and Colville-Nash, 2000). The outcomes of our study revealed that the arsenic caused a substantial escalation in the concentration of these inflammatory biomarkers owing to increased OS levels which reflects the state of inflammation in the heart tissues. Supplementation of PCHP effectively reduced the stimulation of NF-κB that serves as the primary catalyst for tissue inflammation. Therefore, it can be inferred that PCHP may have substantial therapeutic action in mitigating the raised proinflammatory biomarkers, owing to its noticeable anti-inflammatory nature.

Apoptosis can be instigated by dysregulation in the homeostasis between apoptotic and antiapoptotic enzymes which are mediated through mitochondrial-independent or dependent cascades (Selimovic et al., 2011). Downregulation of Bcl-2 and concurrent upregulation of Bax markedly disrupt the integrity of the mitochondrial membrane (Reed, 2006). Bcl-2 & Bax mediates the secretion of cytochrome c from the mitochondrial system which ultimately triggers the process of apoptosis (Shou et al., 2002). Caspase-3 is recognized as a pivotal mediator of apoptosis which activates other pro-apoptotic markers (D’Amelio et al., 2012). Treatment with arsenic resulted in a substantial upsurge in the Bax & Caspase-3 following a remarkable decline in the Bcl-2 concentration, However, PCHP supplementation alleviated arsenic caused cardiac apoptosis by reducing the Caspase-3 & Bax levels while upregulating the levels of Bcl-2.

A normal histo-architectural integrity of any organs is essential for its physiological functions (Oyeyipo et al., 2010). In the current study arsenic exposure remarkably induced histopathological disruptions in cardiac tissues i.e., myocardial damage, fibrosis, inflammatory responses, modification in cellular morphology as well as cellular necrosis. OS is recognized as central element underlying these morphological disturbances (Goyal et al., 2016). ROS disrupts normal activity of mitochondria, resulting in decreased ATP formation which leads towards the cell death in the cardiac tissues. Besides, OS triggered cascade of inflammatory events, instigating myocardial inflammation (Fabiani et al., 2011). Furthermore, these detrimental alterations influence contractility and cardiac perfusion, thus triggering the proliferation of wide range of cardiovascular pathologies (Fabiani et al., 2011). Our findings demonstrated that PCHP is an effective curative compound which recovered aforesaid cardiac histopathological damages provoked by arsenic.

5 Conclusion

Taken together, arsenic reduced the activities of antioxidant enzymes while upregulating the levels of oxidative stress. Furthermore, arsenic promoted the levels of cardiac injury as well as inflammatory markers. The levels of pro-apoptotic markers were escalated while the levels of anti-apoptotic markers were reduced following the arsenic treatment. Moreover, arsenic instigated various histopathological impairments. However, PCHP treatment protected the cardiac tissues via regulating abovementioned dysregulations.

CRediT authorship contribution statement

Syeda Sania Zahara: Writing – review & editing, Writing – original draft, Methodology, Investigation, Conceptualization. Mehrab Khalil: Writing – original draft, Validation, Methodology, Investigation. Moazama Batool: Visualization, Validation, Software, Formal analysis, Data curation. Muhammad Faisal Hayat: Writing – review & editing, Writing – original draft, Methodology, Investigation. Bader O. Almutairi: Writing – original draft, Resources, Funding acquisition. Mian Nadeem Riaz: Writing – original draft, Visualization, Validation.