Ameliorative effects of acetyl-L-carnitine on corpus callosum and functional recovery in demyelinated mouse model

New Insight into the Possible Roles of L-Carnitine in a Rat Model of Multiple Sclerosis

OBJECTIVE

We investigated the effect of L-carnitine (LC) on cuprizone (Cup) demyelinating rat model and its possible underlying mechanisms.

METHODS

Thirty male Sprague-Dawley (SD) rats were randomly allocated to three groups: the normal control group; the Cup group, in which Cup was administrated at a dose of 450 mg/kg per day orally via gastric gavage for 5 weeks; and the Cup + LC group, which received the same dose of Cup as the Cup group, except that the rats were treated additionally with LC 100 mg/kg/day orally for 5 weeks. The nerve conduction (NCV) in isolated sciatic nerves was measured; then, the sciatic nerves were isolated for H&E staining and electron microscope examination. The expression of myelin basic protein (MBP), IL-1β, p53, iNOS, and NF-KB by immunohistochemistry was detected in the isolated nerves. A PCR assay was also performed to detect the expression of antioxidant genes Nrf2 and HO-1. In addition, the level of IL-17 was measured by ELISA.

RESULTS

There was a significant reduction in NCV in the Cup group compared to normal rats (p < 0.001), which was significantly improved in the LC group (p < 0.001). EM and histopathological examination revealed significant demyelination and deterioration of the sciatic nerve fibers, with significant improvement in the LC group. The level of IL-17 as well as the expression of IL-1β, p53, iNOS, and NF-KB were significantly increased, with significant reduction expression of MBP in the sciatic nerves (p < 0.01), and LC treatment significantly improved the studied parameters (p < 0.01).

CONCLUSION

The current study demonstrates a neuroprotective effect of LC in a Cup-induced demyelinating rat model. This effect might be due to its anti-inflammatory and antioxidant actions.

Remyelination in Multiple Sclerosis: Findings in the Cuprizone Model

Remyelination therapies, which are currently under development, have a great potential to delay, prevent or even reverse disability in multiple sclerosis patients. Several models are available to study the effectiveness of novel compounds in vivo, among which is the cuprizone model. This model is characterized by toxin-induced demyelination, followed by endogenous remyelination after cessation of the intoxication. Due to its high reproducibility and ease of use, this model enjoys high popularity among various research and industrial groups. In this review article, we will summarize recent findings using this model and discuss the potential of some of the identified compounds to promote remyelination in multiple sclerosis patients.