Serum lipids, proteins and electrolyte profiles in rats following total body irradiation.

OBJECTIVE: Serum lipid and electrolyte imbalances are common in critically ill patients undergoing radiation therapy. Although multiple disease states and medication may be responsible for the development of these disorders, the aim of this research is to sequentially document the effect of total body radiation on body function utilizing the sequential changes in the serum lipids, electrolytes and protein in rats. METHODS: Serum protein and lipids contents were assessed using kits while electrolytes were assessed with flame photometry in rats exposed to total body irradiations of 1.27 Gy/min in cumulative doses to the fourth irradiation at five-day intervals. RESULTS: Total cholesterol and triacylglycerols serum levels were significantly reduced by irradiation (p < 0.05). No significant differences between experimental and control groups for HDL-C serum levels were detected. Serum electrolyte concentration remained within the normal range after each total body irradiation. Sodium, bicarbonate and chloride were significantly (p < 0.05) higher than control while potassium and creatinine were significantly reduced after the first irradiation only. Sodium/potassium ratio was significantly (p < 0.05) elevated. Serum protein was significantly (p < 0.05) elevated with increasing radiation. CONCLUSION: There are subtle but significant changes in serum lipids, electrolytes and protein after total body irradiation of normal rats. These variations could be due to non-specific stress reactions; as such, they are important markers in radiation induced injury diagnosis.

Experimental malaria: the in vitro and in vivo blood pressure paradox.

OBJECTIVE: Malaria causes more deaths worldwide than any other parasitic disease. Many aspects of the biology that governs the pathogenesis of this parasite are still unclear. Therefore insight into the complexity of the pathogenesis of malaria is vital to understand the disease, particularly as it relates to blood pressure. METHODS: In vivo and in vitro experimental models were used for this study. In the in vivo study, mean arterial pressure, pulse rates and heart rates were recorded by cannulation of the carotid artery of rats. In the in vitro study, ring preparations of blood vessels from the rat aorta were studied using standard organ bath techniques. Dose-response curves for phenylepherine (PE) - and acetylcholine (Ach) -induced relaxation were constructed for rings pre-contracted with PE. RESULTS: Our results showed a significant (p < 0.05) reduction in the mean arterial pressure and pulse rates, while the heart rates remained unaltered in rats with malaria parasites, compared with the controls. Incubation of rat aortic rings with parasitised blood resulted in a significant (p < 0.05) increase in maximum contractile response to phenylephrine in the rat aortic rings but there was no effect on the baseline. The dose-response curve showed a significant (p < 0.05) leftward shift following the addition of parasitised blood and the EC(70) (M) values increased from 7 × 10(- 7) to 5 × 10(-6) M. Following exposure to parasitised blood, the magnitude of Ach-induced relaxation responses reduced significantly (p < 0.05) from 73 ± 3.6 to 24.75 ± 7.25% in the rat aortic rings. CONCLUSIONS: The results suggest that malaria parasitaemia caused in vivo reduction in blood pressure, and enhanced the responses to contractile agents and reduced relaxation responses to acetylcholine in vitro. This appears to be a paradox but is explainable by the complex cardiovascular control mechanisms in vivo. This may be independent of direct action on vascular smooth muscle.

In vivo distribution of lead in male and female rats after intraperitoneal and oral administration.

The resultant effects of lead exposure are seen in almost all the systems of the body and results in toxicity to many organs. Since toxicity depends on its degree of uptake, distribution and metabolism, the authors investigated the differential uptake, accumulation and distribution of lead in organs of males and female Wistar rats following various routes of administration. Group 1 served as control male and control female; group 2 males and females received 5 mg/kg body weight of lead intraperitoneally for 8 days while group 3 males and female rats were administered drinking water containing 100 ppm of lead acetate for 18 days. Tissues were collected for analysis of the lead content using atomic absorption spectroscopy. The relative retention of lead by the tissues was greater in rats exposed to lead by the i.p. route varying in the order of accumulation / uptake in males as lungs > spleen > stomach > kidney > blood > heart and in females as spleen > stomach > heart > kidney > blood > lungs (i.p. route) and (oral route) as for males kidney > lungs > stomach > blood > heart > spleen, and females as kidney > lungs > stomach > blood > heart > spleen. Male Wistar rats showed more accumulation with oral exposure in lungs, spleen and blood with values for kidney and stomach being significantly (p < 0.05) higher when compared with females. Female Wistar rats showed more accumulation with i.p. exposure for spleen and stomach tissues while values for the heart was significantly (p < 0.05) higher than the males. Our findings suggest that lead retention and the organ distribution varied depending upon the sex and route of lead administration.

Effect of Gongronema latifolium ethanol leaf extract on gastric acid secretion and cytoprotection in streptozotocin-induced diabetic rats.

OBJECTIVES: Gongronema latifolium leaves have been used in folklore medicine to manage diabetes mellitus and alleviate dyspepsia. This study aimed to provide a pharmacological basis to the medicinal use ofGongronema latifolium as an antidiabetic and antiulcerogenic agent in diabetes mellitus. METHODS: Ethanol extract from the leaf (200 mg/kg bodyweight) of Gongronema latifolium was administered to both streptozotocin-induced diabetic and control groups orally for 14 days. Gastric acid secretion was measured and ulcer was induced using ethanol and four-hour pyloric ligation. RESULTS: The mean bodyweight was significantly lower (p < 0.01), while the mean weight of the stomach, liver and small intestine to bodyweight ratio was increased significantly (p < 0.05) in the two diabetic groups compared to control. Extract significantly (p < 0.01) reduced the blood glucose level similar to the non-diabetic control. Basal and stimulated acid secretion in diabetic control rats was significantly (p < 0.01) decreased when compared to control. Extract administration increased the stimulated gastric acid secretion to a level significantly (p < 0.05) higher than control while reduction in gastric secretion by ranitidine was similar compared with control. Gongronema latifolium treatment significantly (p < 0.05) reduced ulcer scores in both ulcer models and increased mucus weight in the diabetic group. CONCLUSION: These results suggest that Gongronema latifolium antiulcerative activity is due to its prevention of chemical-induced stomach injury.

Proteins and liver function changes in rats following cumulative total body irradiations.

OBJECTIVE: Total body irradiation (TBI) is a choice therapy for the management of some malignancies; it is also a major cause of oxidative stress. The aim of this research is to sequentially document the effect of total body radiation on body function utilizing the sequential changes in liver function enzymes and proteins in rats. METHODS: Serum protein and liver enzymes were assessed using kits in rats exposed to total body radiations of 1.27 Gy/minute in cumulative doses to the fourth radiation at five-day intervals. RESULTS: Aspartate aminotransferase (AST), alanine transaminase (ALT) and serum protein were significantly (p < 0.05) elevated with increasing radiation. No significant differences between experimental and control groups for bilirubin concentrations were noted at any time. Serum levels of albumin were significantly (p < 0.05) increased with the first to third radiation exposures but reduced at the fourth cumulative dose exposure. CONCLUSION: Variations are associated with acute stress, inflammation which could be due to nonspecific stress reaction, while fluctuations could arise as a result of tolerance and repair within the liver These tests are significant for diagnosis of radiation-induced injury and can be important for evaluation of its severity and correct management.

Altered vascular reactivity induced by malaria parasites.

OBJECTIVE: In this study, we have examined the possibility that there is altered vascular reactivity due to the direct interaction between parasitized erythrocytes and vascular endothelial cells. METHOD: Ring preparations of rat aorta were studied using standard in vitro techniques, the rings were mounted in 20 ml organ baths containing PSS under an initial load of 1 g, maintained at 37 degrees C at pH 7.4 and isometric contractions were recorded electronically. Rings were allowed 90 minutes to equilibrate before the commencement of the various protocols: Dose responses to phenylephrine (PE) and other vasoactive agents (high-K+). Acetylcholine (Ach)--induced relaxation in phenylephrine-contracted rings (pre-contraction was induced by EC70 concentration of phenylephrine). Ach-induced relaxation in PE-precontracted, endothelium-denuded rings. Also, relaxation responses to acetylcholine was investigated through application of a single. (EC70) concentration of acetylcholine in rings exposed to blood with varying concentrations and dilutions of parasitized blood and varying durations of exposure. RESULTS: Incubation with parasitized blood resulted in a significant increase in maximum contractile response to phenylephrine in the rat aortic rings (p < 0.05) but no effect to the base line. Analysis of the whole dose-response curve (using paired t-test) showed a significant left-ward shift following the addition of parasitized blood (p < 0.05), EC70 (M) values increasing from 7 x 10(-7) to 5 x 10(-6)M. Following exposure to parasitized blood, the magnitude of Ach-induced relaxation responses reduced significantly from 73 +/- 3.6 to 24.75 +/- 7.25% in rat aortic rings (p < 0.05). Ach relaxations were significantly enhanced (p < 0.05) at 5-minute exposure; however at longer durations, Ach-relaxations were variable and inconsistent. The lesser the dilution, due to increased volume of parasitized blood, the lesser the relaxation response. Following endothelium removal, there was a marked impairment in endothelium-dependent relaxation responses to ACh in both the control and incubated vessels. Exposure to parasitized blood did not significantly alter contractile responses induced by potassium depolarization. CONCLUSIONS: This gives evidence in support of an endothelium-dependent action of malaria parasites as vascular effects of malaria parasites are mediated, at least in part, via endothelium-dependent mechanism(s).

Comparative study on the efficacy of Garcinia kola in reducing some heavy metal accumulation in liver of Wistar rats.

Garcinia kola is regarded as an antidote and anti-hepatotoxic agent. We examined its protection ability against mercury (Hg), lead (Pb) and cadmium (Cd) accumulation in the liver. The ground seed was mixed with rat feed (5%, w/w) and fed to rats while Hg (10 ppm), Cd (200 ppm) and Pb (100 ppm) was given in drinking water. Garcinia kola was administered either at the same time with the metals (group 2), a week after exposure to heavy metals (group 3) or given a week before heavy metal exposure (group 4) for six weeks. The heavy metal accumulations in the liver were determined using AAS. Garcinia kola could not reverse the weight reduction in the heavy metal exposed groups although it offers more protection and aid greater elimination of heavy metals from the liver. There was a significant (P<0.01) increase in protection by Garcinia kola to Cd (72.4%) and Pb (56.2%) accumulation when compared to Hg (40%) at week 2 which was significantly (P<0.01) decreased at week 4 when compared to week 2. At week 6, the percentage protection to both Hg (64.2%) and Cd (62.2%) were comparable to each other while protection to Pb (49.9%) accumulation was significantly (P<0.01) reduced. The percentage protection was time-dependent in some groups but treatment during and after the exposure provided a greater protection. Garcinia kola has the highest hepatoprotective effect to Cd followed by Hg and least protection against Pb toxicity in rats and its administration is beneficial in reducing heavy metal accumulation in the liver.

Estimation of absorbed cadmium in tissues of male and female albino rats through different routes of administration.

The resultant effects of cadmium exposure are seen in almost all the systems of the body, however, this study is designed to quantify its accumulation in tissues of animals exposed to cadmium. The rats were divided into two distinct groups of males and females, which were then divided into three groups, each for the monitoring of exposure. Group 1 served as control male and female and received normal rat chow and tap water. Group 2 males and females were treated with 5 mg/kg body weight of cadmium chloride (Cd) intraperitoneally for eight days while Group 3 males and females rats received 100 ppm of Cd in drinking water for 18 days. The concentrations of cadmium were analyzed in tissues (lung, stomach, kidney, heart, spleen, blood) by AAS. There were significant (P<0.05) increase in Cd (ppm) accumulation in males compared with females lungs (2.253 ± 1.47 vs 0.317 ± 0.001), stomach (0.187 ± 0.094 vs 0.045 ± 0.032) and blood (0.070 ± 0.001 vs 0.001±0.001) when Cd was administered intraperitoneally. Following oral administration, there were significant (P<0.05) difference in Cd (ppm) content between males and females (kidney (0.506 ± 0.074 vs 0.748 ± 0.147), stomach (0.045 ± 0.020 vs 0.001± 0.001) and blood (1.126 ± 0.001 vs 0.114 ± 0.001). Our results suggest that Cd accumulation in the various organs was sex and route of exposure-dependent in rats.

Antihypertensive properties of Allium sativum (garlic) on normotensive and two kidney one clip hypertensive rats.

Allium sativum (garlic) is reported to act as an antihypertensive amidst an inconsistency of evidence. In this study, we investigated the cardiovascular effects of aqueous garlic extracts (AGE) on normotensive and hypertensive rats using the two-kidney one-clip (2K1C) model. Mean arterial blood pressure (MAP) and heart rate (HR) were measured in normotensive and 2K1C rat models anesthetized with thiopentone sodium (50 mg/kg body weight i.p.) through the left common carotid artery connected to a recording apparatus. The jugular vein was cannulated for administration of drugs. Intravenous injection of AGE (5-20 mg/kg) caused a significant (p<0.05) decrease in both MAP and HR in a dose-dependent manner in both the normotensive and 2K1C models, with more effects on normotensive than 2K1C rat model. The dose of 20mg/kg of AGE significantly (p<0.05) reduced systolic (16.7 ± 2.0%), diastolic (26.7 ± 5.2%), MAP (23.1 ± 3.6%) and HR (38.4 ± 4.3%) in normotensive rats. In 2K1C group, it significantly reduced systolic (22.2 ± 2.1 %), diastolic (30.6 ± 3.2%), MAP (28.2 ± 3.1%) and HR (45.2 ± 3.5%) from basal levels. Pulse pressure was significantly elevated (33.3 ±5.1%) in the 2K1C group. Pretreatment of the animals with muscarinic receptor antagonist, atropine (2 mg/kg, i.v.), did not affect the hypotensive and the negative chronotropic activities of the extract. AGE caused a decrease in blood pressure and bradycardia by direct mechanism not involving the cholinergic pathway in both normotensive and 2K1C rats, suggesting a likely involvement of peripheral mechanism for hypotension.

Specificity of vascular reactivity and altered response in experimental malaria.

OBJECTIVE: Adherence of erythrocytes infected with Plasmodium falciparum (P falciparum) to microvascular endothelial cells (sequestration) is considered to play an important role in parasite virulence and pathogenesis. In this study, we have examined the possibility that there is altered vascular reactivity due to the direct interaction between the parasitized erythrocytes and vascular endothelial cells and that it could be tissue specific. METHOD: Ring preparations of blood vessels from the rabbit carotid and rat aorta were studied using standard organ bath techniques. Dose response curves for phenylephrine (PE) and acetylcholine (Ach)-induced relaxation were constructed in rings pre-contracted with PE. RESULTS: Incubation of rat aortic rings with parasitized blood resulted in a significant (p < 0.05) increase in maximum contractile response to phenylephrine in the rat aortic rings but there was no effect on the rabbit carotid artery. The dose-response curve showed a significant (p < 0.05) left-ward shift following the addition of parasitized blood. Parasitised blood had no effect on baseline in both tissues. Following exposure to parasitized blood, the magnitude of Ach-induced relaxation responses reduced significantly (p < 0.05) in rat aortic rings and (p < 0.05) in rabbit carotid rings; relaxations to acetylcholine was more pronounced in the aortic compared to the carotid rings. CONCLUSIONS: Malaria altered vascular reactivity through an endothelium-dependent mechanism. The regulation of vascular tone by various vasoactive agents following exposure to malaria parasites might be altered in a vessel-specific manner. This may contribute to or exacerbate the abnormal haemodynamics observed in the microcirculation of numerous vascular beds in malaria.