Neuroactive steroid levels in a transgenic rat model of CMT1A neuropathy

Charcot-Marie-Tooth type 1A (CMT1A) represents 80% of all the demyelinating hereditary motor and sensory neuropathies. As recently suggested, neuroactive steroids may have a role in a therapeutic strategy for peripheral neuropathies, including CMT1A. To this aim, an accurate qualitative and quantitative analysis of neuroactive steroid levels in this disease could be extremely important to define effective pharmacological strategies. We here analyzed by liquid chromatography-tandem mass spectrometry the levels of neuroactive steroids present in the sciatic nerve of male and female peripheral myelin protein 22 transgenic rats (PMP22(tg) rats; i.e., an experimental model of CMT1A) and of the corresponding wild-type littermates. We observed that, both in PMP22(tg) rats and in the wild types, the levels of neuroactive steroids, such as progesterone, tetrahydroprogesterone (THP), isopregnanolone (3 beta,5 alpha-THP), testosterone, dihydrotestosterone, and 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol) are sexually dimorphic. It is interesting to note that the levels of 3 beta,5 alpha-THP and of 3 alpha-diol, which are exclusively detectable in sciatic nerve of female and male rats, respectively, are strongly decreased in PMP22(tg) rats. 3 beta,5 alpha-THP and 3 alpha-diol are modulators of gamma-amino butyric acid A receptor. Thus, the present findings may be considered an interesting background for experiments aimed to evaluate the possible therapeutic effects of modulators of this neurotransmitter receptor in male and female PMP22(tg) rats.