Protective Effect of Rifampicin on Microcystin-lr Induced Physiological and Haematological Changes in Rats

The cyclic peptide toxins microcystins and nodularins are the most common and abundant cyanotoxins present in diverse water systems. They have been the cause of human and animal health hazard and even death. Microcystn-LR (MC-LR) is the most common and toxic among the micrcoystin variants. The physiological effects of MC-LR have not been adequately addressed. We report here the results of our study on acute dose of MC-LR (125 μg/kg; intraperitoneal) on certain haematological and physiological effects in rats. The protective effect of a chemoprotector, rifampicin (25 mg/kg; intraperitoneal; 1 h pre-treatment) on reversal of MC-LR induced haematological and physiological parameters was also evaluated. MC-LR significantly decreased WBC count and mean corpuscular volume and the platelet count increased by 1.7 fold over control. The rifampicin alone did not produce any significant change and prevented all the haematological alterations caused by MC-LR. The physiological end points such as mean arterial pressure, heart rate and respiratory rate showed significant decrease with increase in time in MC-LR treated group. In rifampicin protected group, the body temperature and respiratory rates were found to be significantly lower. The results of this study, especially the increase in platelet count and drastic decrease in blood pressure clearly indicate the inflammation caused by acute toxicity of MC-LR. Rifampicin pretreatment could prevent the MC-LR induced lethality and reverse many of haematoligical and physiological effects.