Oral acute toxicity study as well as tissues oxidative stress and histopathological disorders in edible camphor administered rats

Sub-lethal Camphor Exposure Triggers Oxidative Stress, Cardiotoxicity, and Cardiac Physiology Alterations in Zebrafish Embryos

Camphor is a terpene ketone with aromatic and volatile properties in nature derived from the bark of Cinnamomum camphora or synthesized from turpentine. Camphor exhibits various biological properties such as anti-microbial, anti-viral, anti-coccidial, and anti-cancer. It is also used as a form of topical medication for skin irritation, joint pain, and as a relief for itching from insect bites. However, even though the high dose of camphor has been documented to be toxic/lethal in humans in different studies, camphor's developmental toxicity has not yet been explored, and its extensive mechanism of action is still unclear. In the present study, we aimed to assess the toxic effects of camphor in zebrafish embryos in the initial developmental stages. The obtained results demonstrated that a sub-lethal dose of camphor caused a decrease in hatching rate, body length, and substantial elevation in malformation rate on zebrafish embryos. On further observation, in the following time frame, curved body and pericardial edema of zebrafish were also observed. Furthermore, exposure to a sub-lethal dose of camphor was also able to trigger cardiotoxicity in zebrafish larvae. Later, on subsequent biochemical analysis, it was found that the antioxidant capacity inhibition and oxidative stress elevation that occurred after camphor exposure might be associated with the inhibition of total superoxide dismutase (SOD) activity and an increase in reactive oxygen species (ROS) and malondialdehyde (MDA) concentration. In addition, compared to the control group, several apoptotic cells in treated zebrafish were also found to be elevated. Finally, after further investigation on marker gene expressions, we conclude that the developmental toxicity of camphor exposure might be associated with apoptosis elevation and oxidative stress. Taken together, the current study provides a better understanding of the developmental toxicity of camphor on zebrafish, a promising alternative animal model to assess the developmental toxicity of chemical compounds.

Neuroprotective role of camphor against ciprofloxacin induced depression in rats: modulation of Nrf-2 and TLR4

BACKGROUND

Depression affects people feeling to be anxious, worried, and restless. They also lose interest in activities, concentrating and appetite, they finally may attempt suicide. Depression is the second chronic disease, as a source of the global burden of disease, after heart disease. Its prevalence elevated seven times during the COVID-19.

AIM

The current study was designed to evaluate camphor neuroprotective role against rats' ciprofloxacin-induced depression.

MATERIALS AND METHODS

Depression was induced by administration of ciprofloxacin (50 mg/kg; orally) for 21 days. Wister albino male rats were divided into five groups. Group I (normal control): rats were given normal saline. Group II: rats received camphor (10 mg/kg; i.p.) for 21 days. Group III (depression control): rats received ciprofloxacin only. Groups IV and V: rats received camphor (5 and 10 mg/kg; i.p.) for 21 days concurrent with ciprofloxacin. Behavior tests as forced swimming test, activity cage, and rotarod were estimated. Oxidative stress and antioxidant biomarkers as malondialdehyde (MDA), nitric oxide (NO), catalase, and nuclear factor erythroid 2-related factor 2 (Nrf-2) besides inflammatory biomarkers as Toll-like receptor 4 (TLR4) and tumor necrosis factor alpha (TNF-α) as well as neurotransmitters were determined. Finally, histopathological examination was done.

RESULTS

Camphor increased catalase and Nrf-2 activities, decreased NO, MDA, TNF-α, TLR4 serum levels, and elevating brain contents of serotonin, dopamine, gamma-amino butyric acid (GABA) and P190-RHO GTP protein with normal neuronal cells of the frontal cortex.

CONCLUSION

Camphor has neuroprotective effect via modulation of Nrf-2 and TLR4 against ciprofloxacin-induced depression in rats.

Oxidative stress-mediated induction of pulmonary oncogenes, inflammatory, and apoptotic markers following time-course exposure to ethylene glycol monomethyl ether in rats

Ethylene glycol monomethyl ether (EGME) has been used in many products usually handled by humans including inks, paints, polishes, brake fluids and so on. This present study therefore, investigated its effect on lung, in a time-course study in male Wistar rats. Animals were orally administered 50 mg/kg body weight of EGME for a period of 7, 14, and 21 days. Following 7 days of oral exposure to EGME, activities of GPx and SOD were significantly increased, as well as levels of K-Ras, c-Myc, p53, caspase-3, TNF-α and, IL-6, while NO level and GST activity were significantly reduced compared with control. At the end of 14 days exposure, GSH level was significantly decreased, while levels of K-Ras, c-Myc, p53, caspase-3, TNF-α, IL-6, NO and the activities of SOD and GPx were significantly elevated with respect to control. After 21 days of EGME administration, levels of Bcl-2, IL-10, GSH and NO as well as GST activity were significantly decreased, while levels of K-Ras, c-Myc, p53, Bax, caspase-3, IL-6, IL-1β, TNF-α, as well as GPx, CAT, and SOD activities were significantly elevated compared with control. Lung histopathology revealed chronic disseminated alveolar inflammation, bronchiolitis, severe alveolar and bronchi hyperplasia, severe disseminated inflammation, thrombosis, and thickened vessels as a result of EGME exposures. Exposures to EGME could trigger lung damage via the disorganization of the antioxidant system, eliciting the up-regulation of inflammatory, apoptotic, and oncogenic markers in rats.

Hepatic oxidative stress, up-regulation of pro-inflammatory cytokines, apoptotic and oncogenic markers following 2-methoxyethanol administrations in rats

2-methoxyethanol (2-ME) is an organic solvent widely used in the manufacture of brake fluids, paints, resins, varnish, nail polish, acetate cellulose, wood coloring, and as a plasticizer in plastics manufacturing. We therefore, investigated its effect on the liver, in a time-course study in male Wistar rats. Animals were orally administered 50 mg/kg body weight of 2-ME for a period of 7, 14, and 21 days. Following 7 days of administration of 2-ME, there was a significant increase in the level of Bax, c-Myc, K-Ras, TNF-α, IL-1β, IL-6, MDA and GPx activity, while the levels of Bcl-2, NO and GSH were significantly reduced compared with control. At the end of 14 days exposure, Bcl-2, and GSH levels, as well as GST activity, were significantly decreased, while levels of Bax, c-Myc, K-Ras, caspase-3, TNF-α, IL-1β, IL-6, MDA and NO were significantly increased compared with control. After 21 days of 2-ME administration, Bcl-2, IL-10, and GSH levels, as well as SOD and GST activities, were significantly decreased, while levels of Bax, c-Myc, K-Ras, caspase-3, p53, TNF-α, IL-1β, IL-6, MDA and NO were significantly increased compared with control. Lastly, liver histopathology confirmed and corroborated the biochemical findings reported above. We therefore, advised that exposures to 2-ME should be strictly avoided as it could trigger hepatic damage through the disorganization of the antioxidant system, up-regulation of inflammatory, apoptotic, and oncogenic markers in rats.

Ethylene glycol monomethyl ether-induced testicular oxidative stress and time-dependent up-regulation of apoptotic, pro-inflammatory, and oncogenic markers in rats

Ethylene glycol monomethyl ether (EGME) is a major component of paints, lacquers, inks, and automobile brake fluids. As a result, exposures to humans are inevitable. We therefore, investigated in this study, its effect on testicular cells in a time-course manner in male Wistar rats. Animals were orally administered 50 mg/kg body weight of EGME for duration of 7, 14, and 21 days. Following 7 days of the administration, levels of NO and GSH were significantly reduced, while levels of c-Myc, K-Ras, caspase-3, IL-6, TNF-α, and IL-1β were significantly increased compared with control. At the end of 14 days exposure, GPx, and SOD activities, as well as IL-10 level were significantly decreased, while levels of c-Myc, K-Ras, p53, Bax, caspase-3, IL-6, TNF-α, IL-1β, and GST activity were significantly elevated compared with control. After 21 days of EGME administration, Bcl-2, IL-10, and NO levels were significantly decreased, while levels of c-Myc, K-Ras, p53, Bax, caspase-3, IL-6, TNF-α, IL-1β, MDA and GST activity were significantly increased compared with control. After 7, 14, and 21 days of EGME administrations, testis histopathology showed severe loss of seminiferous tubules, the seminiferous epithelium revealed very few spermatocytes, spermatids, spermatogonia, spermatozoa, and Sertoli cells, while the interstitial tissue is eroded, with scanty abnormal Leydig cells, compared with the control that appeared normal. We therefore, concluded that EGME-induced testicular toxicity as a result of EGME administration could be via the disorganization of the endogenous antioxidant systems as well as up-regulation of pro-inflammatory, apoptotic and oncogenic mediators in rats.

Methyl cellosolve-induced renal oxidative stress and time-dependent up-regulation of pro-inflammatory cytokines, apoptotic, and oncogenic markers in rats

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MC significantly increased and decrease the kidney levels of MDA and NO respectively after 14 and 21 days.

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MC administration resulted in the disorganization of the renal redox system.

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MC significantly increased the kidney levels of TNF-α and IL-6 after 7, 14 and 21 days, and IL-1β after 14 and 21 days.

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MC significantly increased kidney p53, Bax, and caspase-3 after 14 and 21 days, and decreased Bcl-2 after 14 and 21 days.

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MC significantly increased the kidney levels of c-Myc and K-Ras after 7, 14 and 21 days.

Methyl cellosolve (MC) is used in production of textile, paints, stains, inks, surface coatings, and anti-icing additive in hydraulic fluids and jet fuel. Consequently, the present study investigated its effect on renal cells, in a time-course study in male Wistar rats. Animals were orally administered 50 mg/kg body weight of MC for a period of 7, 14, and 21 days. Following 7 days of administration of MC, there was a significant increase in the levels of K-Ras, c-Myc, TNF-α, IL-6 and NO, while GSH level and SOD activity were significantly reduced compared with control. At the end of 14 days exposure, RKW, GSH, NO, and Bcl-2 levels were significantly decreased, while levels of K-Ras, c-Myc, p53, Bax, caspase-3, TNF-α, IL-1β, IL-6, MDA and GPx activity were significantly increased compared with control. After 21 days of MC administration, RKW, GSH, NO, IL-10 and Bcl-2 levels were significantly decreased, while levels of K-Ras, c-Myc, p53, Bax, caspase-3, TNF-α, IL-1β, IL-6, MDA and GST activity were significantly increased compared with control. Exposures to MC in any way should be strictly avoided as it could trigger renal damage through the disorganization of the antioxidant system, up-regulation of inflammatory, apoptotic, and oncogenic markers in rats.

Four-week intravenous repeated dose toxicity study of vitacamphorae injection in rats

The study was undertaken to evaluate the safety of vitacamphorae (VCP) injection in Sprague-Dawley (SD) rats. Rats were intravenously administered with VCP at the doses of 0, 5, 15, and 50 mg/kg/day (equivalent to 0, 5, 15, and 50 times the clinical equivalent dose) for 4 weeks, respectively. In addition, we also tested oxidative stress-related parameters and cytokine levels in rat serum. In the current study, intravenous administration of VCP at a dose of 50 mg/kg/day caused significant pathophysiological responses in rats. Compared with the control group, different doses of VCP exposure had no significant effect on body weight, food consumption, and clinic pathology of rats after 4 weeks of VCP administration. Rats in high-dose group (50 mg/kg/day) showed general symptoms of convulsions after VCP administration. The toxicological significance of VCP exposure in the spleen of high-dose female rats was observed, which showed a significant increase in the relative spleen weights (P < 0.01) and mild lymphocyte proliferation in splenic pathology. Furthermore, the results of oxidative stress and cytokine detection showed that the levels of antioxidant enzymes SOD increased in each administration group, but the levels of a series of pro-inflammatory cytokines IL-1β, IL-6, IL-8, IL-12, and IFN-γ also increased in these groups. Above changes caused by VCP exposure can be reversed after 4 weeks of recovery. Overall, the results showed that the no-observed-adverse-effect-level (NOAEL) of VCP injection for 4-week toxicity was 15 mg/kg/day.

Renal and testicular up-regulation of pro-inflammatory chemokines (RANTES and CCL2) and cytokines (TNF-α, IL-1β, IL-6) following acute edible camphor administration is through activation of NF-kB in rats

Camphor-induced oxidative stress and histopathological changes (in brain, lung, liver, kidney and testes) have been reported. We therefore investigated the effect of various doses of camphor in an acute study, on renal and testicular levels of some pro-inflammatory mediators in male wistar rats. Twenty rats divided into four groups of five rats each were used in this study. Group 1 served as control and was administered 6 mL/kg olive oil, the vehicle for camphor, while groups 2, 3 and 4 were orally administered 1000, 2000, and 4000 mg/kg body weight camphor, for seven days. Compared with control, levels of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and interleukin 6 (IL-6) were significantly increased kidney and testes by 2000 and 4000 mg/kg body weight, while interleukin 10 (IL-10) was only significantly increased by 1000 mg/kg body weight of camphor in both tissues. Also compared with control, all doses of camphor administered resulted in a significant increase in the expressions of renal and testicular nuclear factor kappa B (NFkB), cyclooxygenase 2 (COX-2), regulated upon activation normal T cell expressed and secreted (RANTES), and monocyte chemo-attractant protein 1 (MCP-1). Conclusively, use and consumption of camphor should be with caution as it could trigger renal and testicular inflammation through activation of NF-kB and up-regulation of pro-inflammatory markers.