Effects of Tilmicosin Phosphate Administration on Echocardiographic Parameters in Healthy Donkeys (Equus asinus): An Experimental Study

Exploration of Tilmicosin Cardiotoxicity in Rats and the Protecting Role of the Rhodiola rosea Extract: Potential Roles of Cytokines, Antioxidant, Apoptotic, and Anti-Fibrotic Pathways

Tilmicosin (TIL) is a common macrolide antibiotic in veterinary medicine. High doses of TIL can have adverse cardiovascular effects. This study examined the effects of Rhodiola rosea (RHO) that have anti-inflammatory, antioxidant, and anti-fibrotic effects on tilmicosin (TIL)-induced cardiac injury targeting anti-inflammatory, antioxidant, apoptotic, and anti-apoptotic signaling pathways with anti-fibrotic outcomes. Thirty-six male Wistar albino rats were randomly divided into groups of six rats each. Rats received saline as a negative control, CARV 1 mL orally (10 mg/kg BW), and RHO 1 mL orally at 400 mg/kg BW daily for 12 consecutive days. The TIL group once received a single subcutaneous injection (SC) dose of TIL (75 mg/kg BW) on the sixth day of the experiment to induce cardiac damage. The standard group (CARV + TIL) received CARV daily for 12 consecutive days with a single TIL SC injection 1 h after CARV administration only on the sixth day of study and continued for another six successive days on CARV. The protective group (RHO + TIL) received RHO daily for the same period as in CARV + TIL-treated rats and with the dosage mentioned before. Serum was extracted at the time of the rat's scarification at 13 days of study and examined for biochemical assessments in serum lactate dehydrogenase (LDH), cardiac troponin I (cTI), and creatine phosphokinase (CK-MB). Protein carbonyl (PC) contents, malondialdehyde (MDA), and total antioxidant capacity (TAC) in cardiac homogenate were used to measure these oxidative stress markers. Quantitative RT-PCR was used to express interferon-gamma (INF-γ), cyclooxygenase-2 (COX-2), OGG1, BAX, caspase-3, B-cell lymphoma-2 (Bcl-2), and superoxide dismutase (SOD) genes in cardiac tissues, which are correlated with inflammation, antioxidants, and apoptosis. Alpha-smooth muscle actin (α-SMA), calmodulin (CaMKII), and other genes associated with Ca2+ hemostasis and fibrosis were examined using IHC analysis in cardiac cells (myocardium). TIL administration significantly increased the examined cardiac markers, LDH, cTI, and CK-MB. TIL administration also increased ROS, PC, and MDA while decreasing antioxidant activities (TAC and SOD mRNA) in cardiac tissues. Serum inflammatory cytokines and genes of inflammatory markers, DNA damage (INF-γ, COX-2), and apoptotic genes (caspase-3 and BAX) were upregulated with downregulation of the anti-apoptotic gene Bcl-2 as well as the DNA repair OGG1 in cardiac tissues. Furthermore, CaMKII and α-SMA genes were upregulated at cellular levels using cardiac tissue IHC analysis. On the contrary, pretreatment with RHO and CARV alone significantly decreased the cardiac injury markers induced by TIL, inflammatory and anti-inflammatory cytokines, and tissue oxidative-antioxidant parameters. INF-γ, COX-2, OGG1, BAX, and caspase-3 mRNA were downregulated, as observed by real-time PCR, while SOD and Bcl-2 mRNA were upregulated. Furthermore, the CaMKII and α-SMA genes' immune reactivities were significantly decreased in the RHO-pretreated rats.

Evaluation of cardiac indices using M-mode echocardiography after administration of metoclopramide and ondansetron in donkeys (Equus asinus): an experimental study

The aim of the present study was to evaluate cardiac indices using M-mode echocardiography after the administration of metoclopramide and ondansetron in donkeys. For this purpose, 10 apparently healthy Egyptian Baladi donkeys (Equus asinus) were used in a crossover prospective study. Two trials were conducted with the administration of metoclopramide hydrochloride anhydrous at a dose of 0.25 mg Kg-1 and ondansetron hydrochloride sodium at a dose of 0.15 mg Kg-1. The control group (placebo) received a total volume of 50 mL of isotonic saline at 0.9%. An echocardiographic examination was performed using a Digital Color Doppler Ultrasound System equipped with a 2-3.9 MHz phased array sector scanner transducer. In general, the fractional shortening (FS%) was significantly affected by the time for metoclopramide (p = 0.031) and ondansetron (p = 0.047) compared with those of placebo, with treatment with metoclopramide provoking significantly higher percentages of FS% at T60 (p = 0.009) and T90 (p = 0.028) compared with those for ondansetron and placebo. The interaction of time x treatment also showed a statistically significant alteration of FS% (p < 0.05), while the values returned to the basal line at T240. Metoclopramide induced a significant decrease in E-point to septal separation (EPSS) at T90 (p = 0.005), and T240 (p = 0.007) compared with ondansetron and placebo. The time x treatment interaction also showed a significant (p < 0.05) variation in EPSS, with values returning to the basal line at T300. Mitral valve opening velocity (DE SLP) values were significantly affected by time (p = 0.004) in the metoclopramide group compared with those of ondansetron and placebo. Administration of metoclopramide and ondansetron provoked significant alterations of DE SLP at T60 (p = 0.039), T120 (p = 0.036), and T300 (p = 0.005) compared with placebo. In conclusion, caution should be exercised when administering both treatments, especially to animals with suspected cardiac problems.

Reference Values and Repeatability of Pulsed Wave Doppler Echocardiography Parameters in Normal Donkeys

Simple Summary

Cardiovascular disease is underreported in donkeys, possibly related to their limited athletic posture and frequent poor performance-related examinations. Reports on treatments for cardiovascular disease are anecdotal in donkey. Normal echocardiographic parameters have been reported in healthy donkeys. The aim of the present study was to establish the reference values and repeatability for Pulsed Wave Doppler echocardiographic variables of the mitral valve, aortic valve and myocardial performance. Two-dimensional Color flow mapping and spectral Doppler modes were performed. For the mitral valve, the mean velocity, pressure gradient and duration of E-wave were 57.7 ± 12.5 cm/s, 1.4 ± 0.7 mmHg and 0.4 ± 0.13 s, respectively. The results of the present study provide the reference values of PW echocardiographic parameters measurements in normal adult donkeys. Such reference values are helpful, especially when confronted with clinical cases with cardiovascular disorders.

Abstract

In the present study, thirty clinically healthy donkeys were used to establish the reference values and repeatability for Pulsed Wave Doppler echocardiographic variables of the mitral valve, aortic valve and myocardial performance. 2-dimensional Color flow mapping and spectral Doppler modes were performed. For the mitral valve, the mean velocity, pressure gradient and duration of E-wave were 57.7 ± 12.5 cm/s, 1.4 ± 0.7 mmHg and 0.4 ± 0.13 s, respectively. The velocity, pressure gradient and duration of the A-wave were 32.3 ± 9.1 cm/s, 0.3 ± 0.04 mmHg and 0.3 ± 0.1 s, respectively. The mitral valve area, pressure half time, pulsatility index (PI), resistance index (RI) and velocity time integral (VTI) were 1.8 ± 0.5 cm², 66 ± 17 ms, 2.8 ± 1.4, 0.9 ± 0.03 and 19.1 ± 5.7 cm, respectively. For the aortic valve, the mean velocity was 64.9 ± 10.4 cm/s, pressure gradient was 1.8 ± 0.4 mmHg, pulsatility index was 1.4 ± 0.3, resistance index was 0.9 ± 0.02, VTI was 25.02 ± 6.2 cm, systolic/diastolic was 19 ± 4.7 and heart rate was 95.7 ± 28.9 per minute. For Myocardial Performance Index (LV)–Tei Index, the mean ejection, isovolumic relaxation, isovolumic contraction time and myocardial performance index were 0.24 ± 0.01, 0.14 ± 0.01, 0.14 ± 0.02 and 1.2 ± 0.1 s, respectively. The results of the present study provide the reference values of PW echocardiographic parameter measurements in normal adult donkeys. Such reference values are helpful, especially when confronted with clinical cases with cardiovascular disorders.

Protective potency of Astragalus polysaccharides against tilmicosin- induced cardiac injury via targeting oxidative stress and cell apoptosis-encoding pathways in rat

Tilmicosin (Til) was purposed to be used in the treatment of a wide range of respiratory diseases in livestock. However, undesirable adverse effects, cardiac toxicity, in particular, may be associated with Til therapy. In the present study, the response of adult rats administered Til subcutaneously at different doses (10, 25, 50, 75, and 100 mg/kg b.w.; single injection) was evaluated. Astragalus polysaccharide (AP) at two doses (100 and 200 mg/kg b.w.; intraperitoneally) was investigated for its potential to counteract the cardiac influences, involving the oxidative stress-induced damage and apoptotic cell death, elicited by the Til treatment at a dose of 75 mg/kg b.w. in rats. Til induced mortalities and altered the levels of the biomarkers for the cardiac damage, particularly in the rats treated with the doses of 75 and 100 mg/kg b.w.; similarly, morphological alterations in cardiac tissue were seen at all studied doses. AP was found to cause a significant (P ˂ 0.05) decline in the levels of impaired cardiac injury markers (troponin, creatine phosphokinase, and creatine phosphokinase-MB), improvement in the antioxidant endpoints (total antioxidant capacity), and attenuation in the oxidative stress indices (total reactive oxygen species, 8-hydroxy-2-deoxyguanosine, lipid peroxides [malondialdehyde], and protein carbonyl), associated with a significant (P ˂ 0.05) modulation in the mRNA expression levels of the encoding genes (Bcl-2, Bax, caspase-3, P53, Apaf-1, and AIF), related to the intrinsic pathway of apoptotic cell death in the cardiac tissue. AP administration partially restored the morphological changes in the rat's heart. The highest protective efficacy of AP was recorded at a dose level of 200 mg/kg b.w. Taken together, these results indicated that AP is a promising cardioprotective compound capable of attenuating Til-induced cardiac impact by protecting the rat cardiac tissue from Til-induced apoptosis when administered concurrently with and after the Til injection.

Reference Values and Repeatability of B-Mode and M-Mode Echocardiographic Parameters in Healthy Donkey (Equus asinus)-The Guide to Assess Healthy Heart

Donkey (Equus asinus), the cheapest form of agricultural power in Egypt, is used principally as draught or pack animals and may also be ridden, or used for threshing, raising water, milling, and other work. The aim of the present study was to provide B-mode and M-mode echocardiographic reference ranges from a sample of population of donkeys (E. asinus) based on the probability theory and statistics. In the present study, B-mode and 2-dimensional guided M-mode echocardiography were performed on 44 clinically healthy donkeys (E. asinus) (22 males and 22 females), without any neither clinical nor echocardiographic evidence of cardiovascular diseases, aged 2-25 year old, and weighed 150-350 kg. The echocardiographic dimensions, including interventricular septum thickness at end diastole, interventricular septum thickness at end systole, left ventricular internal diameter at end diastole, left ventricular internal diameter at end systole, left ventricular posterior wall thickness at end diastole, and left ventricular posterior wall thickness at end systole were assessed. The cardiac function indices, including end diastolic volume, end systolic volume, stroke volume, ejection fraction, and fractional shortening were also measured. B-mode and guided M-mode echocardiographic examination of healthy donkeys revealed that both the interventricular septum thickness and the left ventricular posterior free wall were greater during systole than diastole. However, the left ventricular dimension during diastole was greater than systole. Furthermore, the recorded data of cardiac function indices, including end diastolic volume, end systolic volume, stroke volume, ejection fraction, and fractional shortening using B-mode echocardiography were closer to those recorded by guided M-mode echocardiography. To our knowledge, this is the first Egyptian study to report the echocardiographic reference ranges of donkeys (E. asinus) based on the probability theory and statistics, the coefficient of variation. The results of the present study can be used as standard and reference values for further echocardiographic studies in donkeys and represent a step in the identification, interpretation, and evaluation of cardiovascular disorders in such animals.

Comparative Effect of Epidural Administration of Xylazine or Dexmedetomidine on Echocardiographic Dimensions and Cardiac Indices in Clinically Healthy Donkeys (Equus asinus)

The aim of the present study was to assess and compare the changes of the echocardiographic dimensions and cardiac function indices after epidural injection of xylazine or dexmedetomidine in clinically healthy donkeys. In an experimental prospective randomized cross-over study, 10 healthy adult donkeys were injected with saline solution, xylazine (0.20 mg kg^-1), and dexmedetomidine (0.005 mg kg^-1) into the epidural space between the second and third coccygeal vertebrae. Echocardiographic dimensions as well as cardiac function indices were assessed using a 2-3.9 MHz sector transducer, at the left paracostal ultrasonographic window, at zero, 15, 30, 60, 90, 120, and 180 minutes after administration of these medications. Epidural injection of xylazine or dexmedetomidine produced moderate sedation, complete bilateral perineal analgesia, and mild ataxia in all studied donkeys. There was a significant (P < .05) decrease in the interventricular septum thickness at end systole 60 minutes, stroke volume 30-120 minutes, fractional shortening 120 minutes, and ejection fraction 90-120 minutes after administration of xylazine or dexmedetomidine when compared with saline solution. Left ventricular end diastolic volume was significantly (P < .05) increased 60 minutes following epidural injection of dexmedetomidine compared with xylazine and saline solution. There was a significant (P < .05) increase in the left ventricular internal diameter at end diastole 90-120 minutes and left ventricular end systolic volume 60-180 minutes after administration of xylazine or dexmedetomidine in comparison with saline solution. In conclusion, epidural use of xylazine or dexmedetomidine in donkeys induced mild and transient effect on echocardiographic dimensions as well as cardiac function indices. Therefore, care should be taken when such medications are to be administered into the epidural space in donkeys with a pre-anesthetic cardiovascular compromise.

Restoring strategy of ethanolic extract of Moringa oleifera leaves against Tilmicosin-induced cardiac injury in rats: Targeting cell apoptosis-mediated pathways

Tilmicosin (Til), an effective macrolide antibiotic, is widely used against respiratory diseases in livestock; however, its treatment is associated with cardiac tissue impairments. In this study, the ethanolic extract of Moringa oleifera (MO) leaves was investigated at two doses (400 and 800 mg/kg body weight [bw], orally) to determine its role in counteracting the effects of Til treatment (75 mg/kg bw) on the cardiac tissue in rats, exploring the oxidative stress-mediated damage and apoptosis. A high dose of MO ethanolic extract elicits considerable changes in the body weight, reduces the mortality rate, neutralizes the impaired cardiac injury markers, improves antioxidant endpoints (total antioxidant capacity, superoxide dismutase, catalase activity, and reduced glutathione level). Also it attenuates the oxidative stress indices (total reactive oxygen species, 8-hydroxy-2-deoxyguanosine, lipid peroxides [malondialdehyde], and protein carbonyl levels) that are associated with Til injection. The co-administration of MO ethanolic extract with Til considerably modulates the expression of apoptosis pathway-encoding genes (Bcl-2, caspase-3, Bax, p53, apoptosis-inducing factor, and Apaf-1), particularly in the high-dose group. Our results support that the concurrent administration of MO ethanolic extract with Til at a dose of 800 mg/kg bw increases the protective activity of the antioxidant system and delays or slows the pathological development of cardiotoxicity mediated by Til injection.

Protective effect of ghrelin against tilmicosin-induced left ventricular dysfunction in rats

This study was conducted to investigate the possible protective effects of ghrelin against tilmicosin-induced acute ventricular dysfunction in rats. Forty adult male Sprague Dawley rats were randomly divided into 4 equal groups: control, ghrelin, tilmicosin, and ghrelin + tilmicosin. The left ventricular structural and functional parameters together with cardiac biomarker levels were evaluated. The results showed that tilmicosin treatment alone significantly decreased the left ventricular fractional shortening, left ventricular ejection fraction, left ventricular stroke volume, and cardiac output when compared with control group. In addition, tilmicosin led to a significant increase in left ventricular internal dimension in systole and left ventricular fractional end-systolic volume. At the same time, serum lactate dehydrogenase, creatine kinase, and creatine kinase-myocardial B fraction levels were significantly increased in tilmicosin-treated group when compared with control group. However, ghrelin pretreatment significantly prevented the left ventricular internal dimension in systole, left ventricular fractional end-systolic volume, left ventricular stroke volume, left ventricular ejection fraction, left ventricular fractional shortening, and cardiac output changes caused by tilmicosin. Moreover, ghrelin pretreatment could reduce significantly serum lactate dehydrogenase, creatine kinase, and creatine kinase-myocardial B fraction levels. These data indicated that ghrelin treatment may provide a protective effect against tilmicosin-induced left ventricular systolic dysfunction.

Donkey Internal Medicine—Part II: Cardiovascular, Respiratory, Neurologic, Urinary, Ophthalmic, Dermatology, and Musculoskeletal Disorders

Cardiovascular diseases are scarcely reported in donkeys, probably linked to their limited athletic attitude and low frequency of poor performance-related examinations. Reports on treatments for cardiovascular pathologies are anecdotal in donkeys. Respiratory tract anatomy shows important differences between horses and donkeys. Donkeys and mules can act as reservoirs spreading many viral, bacterial, and parasitic infectious respiratory diseases. Mosquito and tick-borne encephalitis have been reported in these species in the later years, and even donkeys are being used as sentinels in some areas to detect these emerging diseases. Management and treatment of lithiases can be transferable from horses; however, the same assumption must still be demonstrated for acute and chronic renal diseases. Ocular pathologies are similar to horses, with corneal ulcers frequently observed. Lameness is a common problem in donkeys, with laminitis as the most reported cause followed by pedal abscess.

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Donkeys are different to horses.

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Numerous physiological and clinicopathologic idiosyncrasies are reported in horses.

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Data published for horses should not be extrapolated for donkeys.

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Specific reference ranges, doses, and protocols have to be used for donkeys.