Degeneration in the CNS and PNS consists of degradation and phagocytosis of axons and their myelin sheath distal to the site of injury. Testosterone is a gonadal sex steroid hormone that plays an important role in the central nervous system (CNS) development. One of the less known testosterone actions is neuroprotection. In this research the neuroprotectective effect of intracerebroventricular (ICV) injection of testosterone on the number of spinal motoneurons after sciatic nerve crush were investigated. Thirty two male wistar rats divided to 4 groups (control, compression, compression +castrattion, compression + testosterone injections, n=8). 4 weeks after compresion the lumber segments of spinal cord were sampled, processed, sectioned serially and stained with toluidine blue (PH=4.65). By using steriological quantitative technique (physical dissector), the number of alpha motoneurons in the right ventral horns of spinal cord were counted and compared between groups. Statistical analyses showed that testosterone injections (1μl, ICV, 4 times, one week interval between injections) significantly (P<0.05) reduced neuronal damage. These results indicated that testosterone has an obvious neuroprotective effect on lumbar spinal motoneurons.

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