Effect of Humic Acid on Oxidative Stress and Neuroprotection in Traumatic Spinal Cord Injury: An Experimental Study.

Objective: Traumatic spinal cord injury (TSCI) is an important health problem especially in developing countries with additional socio-economic loss. Humic acids (HA) usually have anti-oxidant, anti-inflammatory, blood-circulating and antiviral effects. We aimed to show effect of HA on neuroprotection in TSCI model.

Methods: We performed TSCI model in Twenty-four Wistar-Albino rats in four groups. Control group underwent only laminectomy. Sham group underwent laminectomy followed by TSCI. Low dose HA (5mg/kg) and high dose HA (10mg/kg) groups underwent laminectomy and TSCI followed by peritoneal administration of HA. Preoperative, postoperative 1st hour and postoperative 24th hour cardiac blood samples were obtained. Total Antioxidant Status (TAS), Total Oxidant Status (TOS) and Oxidative Index (OI) levels were evaluated in serum. The 24th hour motor functions were evaluated by Modified Tarlov Score.

Results: There were no significant changes in TAS values between sham- low dose and high dose humic acid groups (p:0.77/0.21). However there were a significant decrease of TOS levels in the 24th hour post operative blood samples comparing the sham group with low dose humic acid group (p=0.02). Pathological evaluation showed a significant decrease in the severity of edema, hemorrhage, Polymorphonuclear leucocytes (PNL) and Mononuclearleucocytes (MNL) /macrophage/microglia when we compare with the control group (p<0.05). There is a significant recovery in paraplegia level as we compared the HA groups with control groups (p<0.001).

Conclusion: In this study, we showed the effects of HA in the early stages of TSCI on oxidative stress, histopathological changes and neurological improvement. It is thought to be a potential therapeutic agent in acute TSCI but needs to be further evaluated by showing proper effect on other neuroprotective pathways in larger series.