Ecological and oral toxicity assessment of urea and camphor oil against Rattus norvegicus rats

Abstract

Background: One of the most challenging pests to control is the wild rat (Rattus norvegicus), which poses serious risks to both human health and the economy. Fertilizers are a more recent method of pest management with various action modes and are considered safe control agents when applied at low doses.

Aim: The present study aimed to examine the toxicological impacts of the contaminated water with urea and camphor oil individually, post-treatment of rats with camphor oil after the pre-treatment with urea and post-treatment of rats with urea mixed with camphor oil after urea pre-treatment against the wild rats (R. norvegicus).

Methods: The study extends to explore the influence of these treatments on the physicochemical parameters of the water administered by rats. Moreover, the effect of the most three toxic treatments was studied on the blood and renal functional parameters and the kidney tissue of rats after 21 days of treatment.

Results: The study showed that urea was more potent than camphor oil when applied individually and increasing the concentration of urea in the pre-treatment or when combined with camphor oil in the post-treatment caused a significant increase in the mortality of rats. The post-treatment of rats with camphor oil only or camphor oil mixed with urea after the pre-treatment with urea induced a synergistic activity against rats. In addition, the exposed water to urea and camphor oil has been modified in physicochemical parameters and formed ulcers and harm to the kidneys of the exposed wild rats.

Conclusion: This study significantly contributes to the ecological and toxicological potential risk indexes of urea and camphor oil together, which are restricted on the perceptible value relevance in the literature of water quality and renal pathology. Therefore, urea and camphor oil represent successful agents for the wild rat's control.

Keywords: Electron microscopy of rat kidney; Hematological parameters; Physicochemical parameters of water; Toxic influence; Urea and camphor oil.

Fig. 1.. Electron micrograph of the kidney cortex components of a normal wild rat indicating Malpighian corpuscle which explains the general morphology of glomerular capillary and podocyte. The podocyte cell body (Pc) has an irregular-shaped nucleus (N) with batches of chromatine materials (Ch), centrally placed in the cytoplasm packed with various inclusions and organelles, and peripheral nucleolus (Ne). The glomerular capillary has filtration slit (FS), primary process (PP), secondary foot processes (SPs), subpodocyte space (SPS), blood capillary (BC), and red blood cells (RBCs) (X 1500) (A). The general morphology of proximal convoluted tubule (PCT) which has round nuclei (N) with peripherally located nucleoli (Ne) and homogenously distributed chromatine (Ch), peripherally placed in a cytoplasm packed with different inclusions and organelles, long microvilli (Mv), and central small lumen (L). These organelles comprise lysosomes (Ly) appear as small rounded vesicles bounded by a single membrane, mitochondria (M) which are numerous exhibiting elongated or round shapes, and abundant glycogen particles (Gl) in the form of rosette-shaped particles (X 4000) (B). The distal convoluted tubule has basal infoldings (IFs), short microvilli (Mv), central large lumen (L), and the same inclusions of PCT (X4000) (C).

Fig. 2.. TEM micrograph of the kidney cortex components of a normal wild rat indicating the general morphology of Malpighian corpuscle showing the general morphology of glomerular capillary and podocyte. The Pc has an irregular-shaped nucleus (N) with batches of chromatin materials (Ch), centrally placed in a cytoplasm packed with different inclusions and organelles, and peripheral nucleolus (Ne). Glomerular capillary has FS, PP, SPS, SP, BC, and RBC (X 2500) (A). PCT has a round nucleus (N) with homogenous distributed chromatine (Ch), peripherally placed in a cytoplasm packed with different inclusions and organelles, and peripherally located nucleolus (Ne), and long microvilli (Mv). These organelles consist of smooth endoplasmic reticulum (SER) and rough endoplasmic reticulum (RER). Lysosomes (Ly) appear as small rounded vesicles bounded by a single membrane. Abundant glycogen particles (Gl) in the form of rosette-shaped particles. Mitochondria (M) are numerous showing elongated or round shapes. (X 6000) (B). The distal convoluted tubule cell has basal IF, short microvilli (Mv), and the same inclusions of PCT (X10000) (C).

Fig. 3.. TEM micrograph of the kidney cortex components of a treated wild rat indicating elongated nucleus (EN), necrotic nucleus (NN), vesicular granules (VG), condensed chromatine (CCh), swollen mitochondria (SM), Damaged mitochondria (DM), lytic cytoplasm (LC), degeneration of the cytoplasmic organelles (DO), marked dilation with inflammatory cells (IC), vacuolation of the cytoplasm (VC), ulcers (U), pigments (P), enlarged PC (EPc), glomerular capillary comprises enlarged FS (EFS), enlarged BC (EBC), enlarged PP (EPP), enlarged SP (ESP) and enlarged fenestrated endothelium (EFE). (A) and (B) shows the kidney cortex of a treated rate exposed to 2% urea + camphor oil at 10% (X 1,400, 2,700, respectively). (C) and (D) shows the kidney cortex of a treated rate exposed to 2% urea (X 1,400, 2,700, respectively). (E) and (F) shows the kidney cortex of a treated rate exposed to 10% camphor oil (X 1,400, 2,700, respectively).