Immunohistochemical properties of sympathetic chain ganglia (SChG) neurons projecting to the porcine testis in animals subjected to hemicastration, castration and testosterone supplementation.

The present study was carried out on sexually mature boars. All the animals were injected with Fast Blue into the right testis and then divided into four groups [(group 1--control (G1), group 2--hemicastreatad (G2), group 3 castrated (G3) and group 4--castrated and injected with testosterone (G4) boars)]. After a survival period of 3 weeks, G1 animals were transcardially perfused. In pigs of G2, right testis was removed, whereas in G3 and G4 animals both testes were removed. The pigs of G4 were injected with testosterone. After two weeks, all the animals were transcardially perfused and then their sympathetic chain ganglia were collected. The ganglia were cut into 12 microm-thick cryostat sections. The sections were stained using antisera against TH or DbetaH, VACHT or CHAT, NPY, VIP, GAL and AR. Testosterone plasma levels were evaluated with ELISA test. In control pigs, testosterone level amounted to 8.51 +/- 1.29 ng/ml, whereas in hemicastrated animals it was 1.72 +/- 0.35 ng/ml. Bilateral orchiectomy resulted in a drastic decline in testosterone level. Administration of exogenous hormone resulted in tremendous increase in its plasma level. In control pigs, FB-positive (FB+) neurons were found in the right and left ganglia. Immunohistochemical staining revealed that approximately 74% of FB+ neurons contained immunoreactivity to TH or DbetaH, whereas approximately 4% of FB+ cells were VACHT-positive. Among FB+/DbetaH+ neurons, 72% contained NPY and less than 1% stained for GAL. All FB+/VACHT+ neurons were also VIP+. Approximately 62% of FB+ somata expressed immunoreactivity to NPY, whereas 6% stained for VIP. In all experimental pigs, numbers of FB+ perikarya immunoreactive to TH (from 21% in G3, 26% in G2 to 29% in G4,) and DbetaH (62% in G2, 58% in G3 and 59% in G4,) were smaller than those found in G1 animals, whereas numbers of neurons displaying immunoreactivity to other substances studied were higher. The most significant increases in the number of immunoreactive cells were observed in regard to those expressing GAL (24% in G2, 30% in G3 and 27% in G4,) and VIP (11% in G2, 12% in G3 and 11% in G4,) whereas less distinct changes were observed in case of neurones which stained to NPY (67% in G2, 70% in G3 and 68% in G4,) and VAChT or ChAT (6% in G2, G3 and G4). The most apparent changes in the immunohistochemical features of FB+ neurons evoked by bilateral castration were observed in G3 pigs, whereas changes found in G4 animals were very similar to those observed in G2 pigs.