Related Experiment Videos
Use of rifampin as an effective chemoprotectant and antidote against microcystin-LR toxicity
S J Hermansky1, S N Wolff, S J Stohs
1School of Pharmacy and Allied Health Professions, Creighton University, Omaha, Nebr.
Abstract:
Microcystin-LR (MCLR) is a potent cyclic heptapeptide hepatotoxin that is produced by the blue-green algae, Microcystis aeruginosa. This organism forms blooms in freshwater lakes and ponds. Following ingestion of contaminated waters, deaths of wildlife and domestic animals frequently occur. Due to the lack of available methods and drugs for treating cases of poisoning with this toxin, development of an effective antidote to this toxin is needed. We have examined the ability of the semisynthetic antibiotic rifampin to prevent the toxicity of a lethal dose of MCLR in mice. A dose of 25 mg/kg rifampin given intraperitoneally coadministered with a lethal dose of MCLR (100 micrograms/kg) or given 30 or 60 min prior to the MCLR prevented deaths in all animals. Seventy-five percent of the mice were protected from lethality when 25 mg/kg rifampin was given 15 min after the administration of MCLR. The coadministration of 17.5 mg/kg rifampin prevented lethality in 50% of the mice treated with MCLR, while 25% of the mice survived when rifampin was administered 15 min after the MCLR. At 10 mg/kg rifampin the time to death following administration of MCLR was extended, but the animals did not survive. The results indicate that rifampin is an effective chemoprotectant and antidote against the toxicity of MCLR in mice which can be successfully administered after exposure to MCLR.
Insights
Rifampin effectively protected mice from lethal microcystin-LR (MCLR) poisoning. This antibiotic acted as a crucial antidote, even when administered after exposure to the potent blue-green algae toxin.
Area of Science:
- Environmental Toxicology
- Pharmacology
- Microbiology
Background:
- Microcystin-LR (MCLR) is a toxic cyclic heptapeptide produced by Microcystis aeruginosa blooms.
- Ingestion of MCLR-contaminated water causes frequent wildlife and domestic animal fatalities.
- There is a critical need for effective antidotes against MCLR poisoning.
Purpose of the Study:
- To investigate the potential of the semisynthetic antibiotic rifampin as an antidote for MCLR toxicity.
- To evaluate the efficacy of rifampin in preventing MCLR-induced lethality in a mouse model.
Main Methods:
- Mice were administered a lethal dose of MCLR (100 µg/kg).
- Rifampin was administered at various doses (10-25 mg/kg) and time points (coadministration, 15, 30, or 60 min prior/post MCLR).
- Survival rates and time to death were recorded to assess rifampin's protective effects.
Main Results:
- Rifampin (25 mg/kg) coadministered or given 30-60 min before MCLR prevented all deaths.
- 25 mg/kg rifampin administered 15 min after MCLR achieved 75% survival.
- Lower doses or delayed administration showed reduced, but still significant, protective effects.
Conclusions:
- Rifampin demonstrates significant chemoprotective and antidote capabilities against MCLR toxicity in mice.
- Rifampin can be successfully administered post-exposure to mitigate the lethal effects of microcystin-LR.
- These findings highlight rifampin as a promising therapeutic agent for microcystin poisoning.