Limb immobilization alters functional electrophysiological parameters of sciatic nerve

Immobilization, used in clinical practice to treat traumatologic problems, causes changes in muscle, but it is not known whether changes also occur in nerves. We investigated the effects of immobilization on excitability and compound action potential (CAP) and the ultrastructure of the rat sciatic nerve. Fourteen days after immobilization of the right leg of adult male Wistar rats (n=34), animals were killed and the right sciatic nerve was dissected and mounted in a moist chamber. Nerves were stimulated at a baseline frequency of 0.2 Hz and tested for 2 min at 20, 50, and 100 Hz. Immobilization altered nerve excitability. Rheobase and chronaxy changed from 3.13±0.05 V and 52.31±1.95 µs (control group, n=13) to 2.84±0.06 V and 59.71±2.79 µs (immobilized group, n=15), respectively. Immobilization altered the amplitude of CAP waves and decreased the conduction velocity of the first CAP wave (from 93.63±7.49 to 79.14±5.59 m/s) but not of the second wave. Transmission electron microscopy showed fragmentation of the myelin sheath of the sciatic nerve of immobilized limbs and degeneration of the axon. In conclusion, we demonstrated that long-lasting leg immobilization can induce alterations in nerve function.

Impact of pituitary FSH purification on in vitro early folliculogenesis in goats

Porcine pituitary follicle stimulating hormone (pFSH) is known to regulate the production of growth factors that have an essential role in early foliculogenesis. However, the effects of different preparations of pFSH on the survival and development of caprine follicles are not yet known. The aim of this study was to evaluate the effects of different pFSH (Stimufol and Folltropin) on the in vitro survival and growth of caprine preantral follicles. Pieces of caprine ovarian tissues were cultured for either one or seven days in a supplemented Minimum Essential Medium, alone or containing either Stimufol (50 ng/mL) or Folltropin (10, 50, 100 and 1000 ng/mL). Fresh control ovarian tissues as well as cultured tissued were processed for histological and ultrastructural studies. The results showed that after seven days, o nly Stimufol maintained follicular morphology similar to control. Moreover, follicular degeneration was higher in medium alone or with Folltropin at 50, 100 and 1000 ng/mL. However, at day seven, the percentage of growing follicles was higher in 100 ng/mL of Folltropin than Stimufol. In conclusion, FSH preparations affect differently the performance of in vitro culture of caprine preantral follicles. Stimufol was better to preserve follicular morphology while Folltropin was more efficient to promote follicular growth.