Triclosan Linked to Impaired Muscle Function

The chemical, triclosan, has been linked to impaired muscle function, according to an emerging study that appears, online, in the Proceedings of the National Academy of Sciences.

As we’ve explained, triclosan was originally developed as a hospital surgical scrub 40 years ago. Its ubiquity has grown and, today, it can be found in a multitude of consumer products, including antibacterial soaps, deodorants, toothpastes, and other personal care consumer products. According to the emerging study, triclosan adversely impacts muscular contractions at the cellular level, said Science Daily. Triclosan was found to slow swimming in fish and diminish muscular strength in mice, say the research team at the University of California, Davis, and the University of Colorado.

“Triclosan is found in virtually everyone’s home and is pervasive in the environment,” Isaac Pessah, professor and chair of the Department of Molecular Biosciences in the UC Davis School of Veterinary Medicine and principal investigator of the study, told Science Daily. “These findings provide strong evidence that the chemical is of concern to both human and environmental health,” Pessah added. Triclosan is also popularly found in mouthwash, bedding, clothing, carpeting, trash bags, and toys.

In 1998, the U.S. Environmental Protection Agency (EPA) estimated that more than one million pounds of the chemical are produced in the United States each year, said Science Daily. In fact, triclosan can be found in the country’s waterways and in aquatic organisms as small as algae and as large as dolphins; triclosan is also detectable in human urine, blood, and breast milk.

For their research, the team conducted a number of experiments looking at the chemical’s effects on muscle activity, utilizing doses that people and animals might experience in normal life, said Science Daily. The so-called “test tube” experiments revealed that triclosan weakened heart muscle cells’ and skeletal muscle fibers’ ability to contract. Typically, explained Science Daily, electrical stimulation—so-called “excitation”—of muscle fibers isolated in experiments, evoked the so-called “excitation-contraction coupling” phenomenon,” which is the basis for muscle movement, such as what is seen in heartbeats. When triclosan is introduced, typical protein communication was impaired, leading to skeletal and cardiac muscle failure, said Science Daily.

Triclosan also impaired heart and skeletal muscle contraction in living animals based on tests conducted on mice, which exhibited a 26 percent heart function reduction within 20 minutes of exposure to triclosan, said Science Daily. The mice also exhibited an 18 percent reduction in grip strength that was evident for up to one hour after having a received a dose of triclosan. Grip strength is a measurement of mouse strength. “The effects of triclosan on cardiac function were really dramatic,” Nipavan Chiamvimonvat, professor of cardiovascular medicine at UC Davis and a study co-author, told Science Daily. “Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant in our models.”

The team also reviewed triclosan’s effects on fathead minnows, a fish often used in studies of aquatic pollutants, and found that minnows exposed to triclosan for seven days revealed considerable swimming activity reduction. “We were surprised by the large degree to which muscle activity was impaired in very different organisms and in both cardiac and skeletal muscle,” Bruce Hammock, a study co-author and professor in the UC Davis Department of Entomology, told Science Daily. “You can imagine in animals that depend so totally on muscle activity that even a 10-percent reduction in ability can make a real difference in their survival.”