EFFECTS OF AQUEOUS EXTRACT OF DISSOTIS BRAZZEI COGN. ROOTS ON BIOLOGICAL PARAMETERS AND RISK FACTORS OF MYOCARDIAL INFARCTION IN NORMAL RATS

The present study aimed to evaluate the effects of the aqueous extract of the roots of Dissotis brazzeiCogn.(D. brazzei), on the parameters of myocardial infarction (MI) and its risk factors in normal rats. Among the cardiac pathologies cited by the population as heartache is the myocardial infarction. D.Brazzeiis a medicinal plant widely used in traditional Congolese medicine to treat heart diseases. In this study, rats were given the aqueous extract of the roots of D. brazzei(125, 250 and 500 mg/kg/day)for 7 days in, comparison with rats treated with distilled water (1 mL/100 g). The results obtained show that this extract has no significant effects on MI parameters (LDH, CK-MB, troponin I and CRP). Moreover, it causes variations at non-risk percentages of MI risk factors (blood pressure, body weight of rats, total cholesterol, HDL-C and Triglycerides). In conclusion, the aqueous extract of the roots of D. brazzei at the studied doses, does not modify the parameters of MI, nor does it promote the occurrence of the risk factors of MI. The evaluation of a cardioprotective study of this extract deserves to be carried out in rats.


Evaluation of the effects of D. brazzeï, on the risk parameters of myocardial infarction in wistar rats On the body weight of normal rats
The effect on body weight consisted in measuring the weight of the above treated rats before treatment (D0) with the different products (distilled water and aqueous extract) and at the end of the treatment (D7).

On the lipid profile of normal rats
The effect on lipid parameters consisted in the determination of total cholesterol, HDL-C and triglycerides from the blood collected in the dry tubes of the above treated rats.

On mass and heart parameters of normal rats
After collection of blood from the above-treated rats, each rat was placed in the supine position and its four legs secured with the needles on a cork board. After dissection, the heart was removed and then weighed, and the left ventricle was also weighed after the right ventricle and atria were removed. Finally, the ratio of heart mass to left ventricle was calculated to determine the left ventricular index (LVI).

Statistical Analysis
The Student-Fischer "t" test was used. The observed difference between the means is significant when the value of "t" calculated in absolute value is, greater than the value of "t" read from the Student-Fischer "t" table for a ddl = n1 + n2 -2 and the risk of first kind of 5%. Table I shows that troponin and CRP tests are negative with the aqueous extract of D. brazzeïroots at the three doses studied as for distilled water. The results presented in Table II show lower levels of CK-MB and LDH in rats treated with aqueous extract of D. brazzeï roots at the dose of 125 mg/kg (12.95 ± 3.040 and 292.2 ± 134.21) compared with those treated at the doses of 250 and 500 mg/kg as well as those treated with distilled water. Similarly, ASAT activity was significantly lower (p < 0.001) in rats treated with aqueous extract of D. brazzeï at different doses (125 ;250 ; 500 mg/kg) than in control rats (distilled water).

Effects of aqueous extract of D. brazzeïroots on hematological parameters influenced by myocardial infarction in normal rats
The effect of aqueous extract of D. brazzeï roots on hematological parameters influenced by myocardial infarction in normal rats is presented in Table III. These results show a significant increase in red blood cells with a value of 7.58 ± 0.01; p < 0.01) ; white blood cells to 8.70 ± 1.34; p < 0.001 ; hemoglobin to 13.14 ± 0.39; p < 0.001; blood platelets to 1196.8 ± 74.46; p < 0.01; lymphocytes to 5.28 ± 1.32; and MHCC to 32.84 ± 0.27; p < 0.01 compared with the control lot. In contrast, a decrease in red blood cell count to 6.17 ± 0.30; p < 0.05 and an increase in MHCC to 32.8 ± 0.19; p < 0.05 at 500 mg/kg compared to control were noted. Table IV, shows the weight evolution of normal rats treated with different doses of the aqueous extract of the roots of D.brazzeï(125 ,250 and 500mg/kg) and with distilled water. The administration of the extract caused from D0 to D7 a weight change of 10.94% at the 500 mg/kg dose ; 14.14% at the 125 mg/kg dose and 17.7% at the 250 mg/kg dose against a change of 2.13% in rats given distilled water.

Effects on Lipid Profile of Normal Rats
The results recorded in Table V show significantly elevated HDL-cholesterol levels (p < 0.01) at 60.96 ± 2.18 and 64.74± 1.17 at the respective doses of (125 and 250 mg/Kg) compared with the control lot. In addition, total cholesterol and triglyceride levels were lower in animals treated with the extract at the different doses compared to those treated with distilled water.

Effects on mass and heart parameters of normal rats
From Table VI, it appears that the aqueous extract of D.brazzeï roots at the doses studied does not cause significant variations in the parameters measured.

Effects on diastolic blood pressure (DBP) in normotensive rats
The results of the evaluation of the effect of the aqueous extract of the roots of D.brazzeïat different doses (5 ;10 ; 20 mg/kg), on the diastolic blood pressure are presented in table VII. The i.v. administration of this extract at doses of 5, 10 and 20 mg/kg in normal rats causes an increase in DBP of 19.25; 3.83 and 1.65 mm Hg respectively against the increase of 1.84 mm Hg in NaCl treated rats (control lot). . Troponin I and CRP test results were negative. This indicates an absence or low level, in the blood, of the two parameters sought. These results suggest that the aqueous extract of D. brazzeïroots at the doses studied would not induce the production of troponin I or CRP. This extract would not induce myocardial lesions or necrosis and therefore could be cardioprotective. Indeed, it is reported that when myocardial cells containing these markers are damaged or destroyed due to insufficient oxygen or glucose supply, the cell membrane becomes permeable or may rupture, resulting in enzyme leakage (Ansari et al., 2019). To confirm or refute this hypothesis, the levels of CK-MB, LDH and ASAT were quantitatively evaluated in rats treated with aqueous extract of D. brazzeï roots (125, 250 and 500 mg/kg). The results obtained reveal lower levels of CK-MB, LDH and ASAT only at the minimum dose of 125 mg/kg compared to the control lot. The effective 486 cardioprotective effect of this extract could be at this dose. These results are different from those of Akpanabiatu et al., (2003) who worked on the aqueous extracts of Eleophorbia drupifera and Artemisia afra leaves in rats.

Discussion:-
The results of the analyses of the hematological parameters show significant elevations of the levels of red blood cells, hemoglobin and CCMH at the dose of 125 mg/kg. An increase in other parameters was noted at 500 mg/kg. According to Babes et al.,(2021), a low hemoglobin level predicts the development of major cardiac events in patients with acute coronary syndrome. The aqueous extract of the roots of D. brazzeïwould thus stimulate the production of blood cells and would consequently prevent cases of anemia. Indeed, lymphocytes modulate the inflammatory response; a low lymphocyte count is associated with more extensive atherosclerosis (Babes et al., 2021;Mehta et al., 1997), as well as with a poor prognosis in patients with myocardial infarction (Babes et al., 2021). This potential would be unfavorable in infarction because of the high level of blood platelets (hemostasis). Our results corroborate those of Odo et al., (2020) who worked on the physiological effects of Duranta erecta (L) leaves on the albino rat, rattus norvegicus.
Modifiable risk factors such as obesity or overweight, dyslipidemia, and high blood pressure predispose to myocardial infarction (Khan et al., 2021 ; Benjamin et al., 2018 ; Boateng and Sanborn, 2013). Administration of the aqueous extract of D. brazzeïroots (125, 250, and 500 mg/kg) for 7 days resulted in a significantly higher change in weight of normal rats compared to that of 2.13% in normal rats given distilled water. This result suggests that this extract causes overweight in rats. These excess weights of more than 10% increase the relative risk of developing ischemic heart disease to 1.4. This risk is elevated to 2 for an excess weight exceeding 30% (Alaya et al., 2002). With this extract, the excess weight is very far from 30% at the doses studied. Concerning the lipid profile, it has been established that high concentrations of triglycerides, total cholesterol, LDL-cholesterol and a decrease in HDL-C levels accelerate the development of atherosclerotic plaques and are thus major risk factors for coronary heart disease and myocardial infarction (Kulothungan and Shaik, 2021 ; ATF, 2012). However, the results obtained show that the aqueous extract of D. brazzeïdoes not significantly influence the serum triglyceride level but decreases the serum total cholesterol level and increases the HDL-C level at the studied doses of this extract compared to the control. Numerous studies have proven that decreasing LDL-C levels and increasing HDL-C levels can prevent the The aqueous extract of D. brazzeï(125, 250, and 500 mg/kg) did not alter heart mass, and the calculated left ventricular index was lower than in control rats. An increase in the mass of the left ventricle leads to a suffering of the heart, which could lead to a myocardial infarction (MI). This extract would therefore not have a direct negative effect on the heart.
The relationship between the level of diastolic blood pressure (DBP) and the risk of developing MI has been demonstrated in several epidemiological studies and has shown that a 30 mmHg increase in diastolic pressure multiplies the risk of MI by 4 (Alaya et al., 2002). The results obtained show different elevations at 30 mmHg of the diastolic blood pressure in rats having received the aqueous extract of D. brazzeïrootsat three (3) doses. These results suggest that this extract does not promote the occurrence of this risk parameter of MI in normal rats.

Conclusion:-
In sum, the results obtained in the present study show that the daily administration of the aqueous extractof D. brazzeïrootsdoes not modify almost all the biological and hematological parameters as well as the risk of the myocardial infarction, in the sense of induction of this pathology. Thus, a study of the cardioprotective potential of this extract is envisaged.    Data are expressed as mean ± SEM ; ns (no : significant), *significant (p<0.05) ; **significant for(p<0.01); ***significant for(p<0.001); RBC: Red blood cells (x103/µL); WBC: White blood cells (x103/µL); HB: