Does circadian rhythm disruption induced by light-at-night has beneficial effect of melatonin on sciatic nerve injury?

Circadian Rhythm Influences the Promoting Role of Pulsed Electromagnetic Fields on Sciatic Nerve Regeneration in Rats

“…Additionally, the dose of melatonin must be high enough to achieve a beneficial effect on nerve regeneration. It has been shown that the levels of melatonin have a circadian fluctuation during the dark–light cycle (56), and there is close relationship between melatonin and CR during the melatonin treatment on nerve injury (57). In addition, other hormones, such as growth hormone (GH) and the related insulin growth factor-1, have also been shown to enhance the survival of motor fibers and axonal branching (58–61).…”

Effect of melatonin supplemented at the light or dark period on recovery of sciatic nerve injury in rats

“…Group III [The SNI plus melatonin at light group]: In this group, sciatic nerve injury was performed and then the rats received melatonin (Sigma, USA), 50 mg/kg i.p, in the light period (Kaya et al, 2013[15]) at 9:00 am daily for 6 weeks.…”

“…For SFI, animals were tested in a confined walkway measuring 100 cm long and 7.5 cm wide with side wall height 15 cm (Kaya et al, 2013[15]). The hind paws of the rats were pressed down onto an inkpad, and they were allowed to walk along a sheet of white paper.…”

Melatonin and its therapeutic actions on peripheral nerve regeneration

“…In line of Atik et al [2], a potent neuroprotective effect to preserve peripheral neural fibres from lipid peroxidative damage after blunt trauma achieved by Shokouhi et al [51] especially at a dose of 50 mg/kg. In our previous studies we also administered 50 mg/kg melatonin after sciatic nerve injury [22,23].…”

“…In another recent study we re-addressed the beneficial effect of melatonin treatment and tried to improve this beneficial effect on cut injury by disruption of the circadian rhythm induced by light-at-night [23]. Although we used the same dose of melatonin as used in previous study [22] and found beneficial effect on sciatic nerve injury evaluated by functional, ultrastructural, biochemical tests; circadian rhythm disruption induced by light-at-night surprisingly did not demonstrate the same effect as expected [23]. We think that further studies need to be conducted to elucidate mechanism of this unexpected effect of melatonin in disrupted circadian rhythm.…”