Influence of Microcystin-LR on the activity of membrane enzymes in rat intestinal mucosa

Abstract

I. M. MORENO, A. MATE, G. REPETTO, C. M. VÁZQUEZ and A. M. CAMEÁN. Influence of Microcystin-LR on the activity of membrane enzymes in ratintestinal mucosa. J. Physiol. Biochem., 59 (4), [293][294][295][296][297][298][299][300] 2003.The objective of the present study was to evaluate the effects of microcystin-LR (MCLR) on the activity of membrane enzymes from intestinal mucosa. In addition, serum chemistry and peroxidative status of both serum and intestinal homogenate were evaluated after treatment with MCLR. Wistar rats were treated with intraperitoneal injection of either 100 µg pure MCLR/Kg body weight or saline solution. A significant increase in liver weight and altered serum enzyme activities were found in MCLR-treated rats, indicating damage to the liver in these rats, as previously suggested. A higher specific activity of sucrase (1.5-fold) was observed after the administration of MCLR, whereas other intestinal apical membrane enzymes, such as lactase, maltase and alkaline phosphatase were not modified by the treatment. The specific activities of acid phosphatase and succinate dehydrogenase, markers for lysosomal and mitochondrial membranes, respectively, were also increased (32% and 60%, respectively) in treated rats. The analysis of lipid peroxidation showed that the peroxidative status was increased in both serum and intestinal mucosa from MCLRtreated rats, reflecting an excess production of oxygen free radicals induced by this cyanobacterial toxin. In conclusion, this study shows that acute exposure to MCLR affects the intestinal physiology by modifying the intestinal peroxidation status as well as the activity of membrane enzymes.

Microcystin-induced variations in transcription of GSTs in an omnivorous freshwater fish, goldfish

“…Liver has been described as the most important organ involved in the regulation of redox metabolism (Klaassen, 2001), due to synthesis of key enzymes responsible for reactive oxygen species clearance and production of the most important systemic antioxidant agent, glutathione (GSH). On the other hand, it has been proven that MC-LR promotes renal and intestinal alterations and affects renal physiology (Nobre et al, 2003;Moreno et al, 2003). Thus, it could be assumed that MCs affected the functions of the detoxification system of these organs.…”

“…MCs are also proved to promote renal and intestine alterations and affect renal physiology (Nobre et al, 2003;Moreno et al, 2003). Anemia caused by MC-induced kidney function impairment is suggested to be responsible for the abnormality of swimming behaviors .…”

The profound effects of microcystin on cardiac antioxidant enzymes, mitochondrial function and cardiac toxicity in rat

“…Oxidative stress is associated with the pathophysiology of many cardiomyopathies, such as anthracycline-mediated cardiomyopathy (Singal et al, 1997;Xu et al, 2001) and alcoholic cardiomyopathy (Edes et al, 1986). Nowadays, accumulating evidences imply that MC-dependent damage is accompanied by oxidative stress in liver, kidney and intestinal mucosa in mammals (Botha et al, 2004;Ding et al, 1998Ding et al, , 2001Moreno et al, 2003Moreno et al, , 2005. Moreover, studies strongly indicate that mitochondria are the vulnerable target of MC.…”

Oxidative stress response after prolonged exposure of domestic rabbit to a lower dosage of extracted microcystins

“…Cyanobacterial extracts can also enhance intracellular production of reactive oxygen species (ROS) (Ding et al, 1998). It is widely reported that MCs induce oxidative stress in many animals: mice, rat and aquatic organisms such as crab and fish (Moreno et al, 2003;Pinho et al, 2005;Prieto et al, 2006;Jayaraj et al, 2006).…”