Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

Toxicol Appl Pharmacol. 2009 Oct 15;240(2):255-64. doi: 10.1016/j.taap.2009.07.001. Epub 2009 Jul 10.

Abstract

Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril+DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology*
  • Apoptosis / drug effects
  • Behavior, Animal / drug effects
  • Biogenic Amines / metabolism
  • Calcium / metabolism
  • Captopril / pharmacology*
  • Chelating Agents / pharmacology*
  • Cytochromes c / metabolism
  • DNA Damage
  • Disease Models, Animal
  • Drug Therapy, Combination
  • Exploratory Behavior / drug effects
  • Lead Poisoning, Nervous System / drug therapy*
  • Lead Poisoning, Nervous System / metabolism
  • Lead Poisoning, Nervous System / pathology
  • Lead Poisoning, Nervous System / physiopathology
  • Learning / drug effects
  • Male
  • Membrane Potential, Mitochondrial / drug effects
  • Memory / drug effects
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Motor Activity / drug effects
  • Nerve Degeneration / chemically induced
  • Nerve Degeneration / drug therapy*
  • Nerve Degeneration / metabolism
  • Nerve Degeneration / pathology
  • Nerve Degeneration / physiopathology
  • Neurons / drug effects*
  • Neurons / metabolism
  • Neurons / pathology
  • Nitric Oxide / metabolism
  • Organometallic Compounds
  • Oxidative Stress / drug effects
  • Rats
  • Rats, Wistar
  • Reactive Oxygen Species / metabolism
  • Succimer / analogs & derivatives*
  • Succimer / pharmacology

Substances

  • Antioxidants
  • Biogenic Amines
  • Chelating Agents
  • Organometallic Compounds
  • Reactive Oxygen Species
  • Nitric Oxide
  • Cytochromes c
  • Captopril
  • monoisoamyl-2,3-dimercaptosuccinate
  • Succimer
  • lead acetate
  • Calcium