Efficiency of Thyme and Oregano Essential Oils in Counteracting the Hazardous Effects of Malathion in Rats

Abstract

The widespread use of MLT may pose numerous hazards to animal breeding, health, and resilience due to the presence of MLT residues in animal feedstuffs, pastures, hay, and cereals. Many medicinal plants provide what is called a generalized anti-toxic remedy. The current study examined hazardous biochemical and histological reactions to MLT and the efficiency of ThEO and OEO essential oils as anti-toxic therapies to return to a natural state after MLT exposure. A total of 75 male albino rats were randomly assigned to two groups: (i) C - MLT, comprising 25 rats, served as the control group; and (ii) C + MLT, with 50 rats that were exposed to 5 mg/kg/BW. After exposure to MLT for 21 days, a return to normal status was determined by subdividing the C + MLT group into two equal groups: ThEO and OEO were used as treatments, with 100 mg/kg body weight of thyme and oregano essential oils, respectively, being administered for 21 days. The results showed a significant decrease in body weight gain (BWG) and final weight (FW) compared to C - MLT, while the therapeutic effects of ThEO and OEO enhanced FW and BWG. Our results indicated that MLT exposure resulted in deficient serum liver function, but that OEO and ThEO therapy brought about a significant improvement in liver enzyme function. Although there was no significant difference in serum aspartate transaminase (AST) or alkaline phosphatase (ALK-Ph) and a significant drop in alanine transaminase (ALT) and acetyl choline-esterase (AChE) levels, the C + MLT group showed hepatic fibrosis in the third stage. Furthermore, histological sections of the OEO and ThEO groups showed reduced hepatocellular damage, inflammation, and hepatic fibrosis. However, there was a significant increase in serum creatinine between the C + MLT and C - MLT groups following exposure to MLT. Histological sections of renal tissue from rats treated with OEO and ThEO showed reduced tubular damage, reduced interstitial inflammation, and preserved renal tissue architecture. In conclusion, OEO and ThEO are potential compounds for use as anti-toxic therapies to return to a natural state after MLT exposure. These compounds could serve as an experimental therapeutic approach against natural toxins, providing a solution to the problems of raising livestock that are exposed to nutritional toxicity.

Keywords: hazards; malathion; oregano essential oils; thyme essential oils; toxicity.

Figure 1

Schematic diagram showing the experimental protocol for the hazards of exposure to malathion and the efficiency of thyme and oregano essential oils as anti-toxic therapies in the rats. Rats were randomly assigned to two groups: (i) C − MLT, in which 25 rats served as the control group; and (ii) C + MLT, where 50 rats were dosed at 5 mg/kg body weight. C − MLT was continued from the earlier experiment, while MLT exposure was terminated after 21 days. The return to a normal state was determined by dividing C + MLT into two equal subgroups and treating them with 100 mg/kg body weight of OEO and ThEO, respectively.

Figure 2

The liver tissue sections in the C − MLT group were stained with H&EC − MLT. (A,B) dotted black circles: normal hepatic nodules. (A,C) Black arrow: Sinusoids contained numerous Kupffer cells. (C,D) Yellow arrow: hepatic macrophages. (D) Black star: hexagonal lobules, each with a central vein at its core. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 3

The liver tissue sections were stained with H&E in the C + MLT group. (A) Black arrow: vacuolar degeneration or fatty change. (A,B) dotted blue circle: liver architecture may have been disrupted, with areas of hepatocellular necrosis and inflammation. (B,D) Black star: central veins and sinusoids may be dilated. (A–D) Blue arrow: a marked degree of hepatic fibrosis. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 4

The kidney tissue sections in the C − MLT group were stained with H&EC − MLT. (A,B) Interstitial inflammation and fibrosis may have been present, reflecting a chronic inflammatory process. (C) Blue arrow: Bowman’s capsules. (D) Yellow arrow: degenerative changes, such as vacuolization or necrosis. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 5

The kidney tissue sections were stained with H&E in the C + MLT group. (A–D) Black arrow: glomerular hypertrophy and hypercellularity. (D) Blue arrow: Bowman’s capsules. (C,D) Yellow arrow: degenerative changes, such as vacuolization or necrosis. (B,C) Black star: extravasation and hemorrhage; dotted blue circle: appeared disrupted, with areas of hepatocellular necrosis. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 6

The liver tissue sections stained with H&E in the OEO group returned to normal status after MLT exposure. (A) Blue dotted circle: necrosis and psychotic nuclei compared to rats exposed to MLT alone. (B,D) yellow arrow: inflammation parenchyma, with fewer infiltrates of inflammatory cells such as lymphocytes and macrophages. (D) Blue arrow: a moderate reduction in hepatic fibrosis. (C,D) Black arrow: a few hepatocytes with vacuolated cytoplasm, indicating lipid accumulation. (A,C) Black star: dilated central vein was detected. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 7

The liver tissue sections stained with H&E in the ThEO group returned to normal status after MLT exposure. (A) Blue dotted circle: few remaining necrosis areas, psychotic nuclei, and inflammatory cell infiltrates. (D) Yellow arrow: accumulation of lipid droplets within hepatocytes. (D) Blue arrow: fibrosis grade persists. (A,C) Black star: dilated central veins. (C,D) Black arrow: hepatocellular necrosis by the presence of pyknotic nuclei and disrupted hepatic cords. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 8

The kidney tissue sections stained with H&E in the OEO group returned to normal status after MLT exposure. (A–D) Black arrow: a nearly normal pattern of liver architecture, with few remaining necrosis areas. (B) Black star: dilated central veins. (C,D) Blue arrow: Mild fibrosis grade persists. (C,D) Yellow arrow: steatosis, or the accumulation of lipid droplets within hepatocytes. The magnification power is ×100 (A,B) and ×400 (C,D).

Figure 9

The kidney tissue sections stained with H&E in the ThEO group return to normal status after MLT exposure. (A–C) Black arrow: a reduction in glomerular size. (C) Blue arrow: a decrease in Boymen’s capsule thickness. (C,D) Yellow arrow: tubular dilation. The magnification power is ×100 (A,B) and ×400 (C,D).