Temporal changes in neurotrophic factors and neurite outgrowth in the major pelvic ganglion following cavernous nerve injury

Abstract

Despite nerve-sparing radical prostatectomy, nerve damage and erectile dysfunction (ED) prevails and preventing neurodegeneration is of great importance. Neurotrophic factors and neurite outgrowth were characterized in major pelvic ganglia (MPG) following bilateral cavernous nerve injury (BCNI). Young male Sprague-Dawley rats underwent sham or BCNI surgery and intracavernosal pressure to mean arterial pressure ratio (ICP/MAP) was measured 2, 7, 14, 21, 30 and 60 days following injury (n=8/group). MPG gene expression (qPCR) and Western blot was performed for glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurturin (NRTN), neurotrophin-3 (NT3), neurotrophin-4 (NT4), brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF) and activating transcription factor 3 (ATF3). Additional rats were injured and MPGs removed 24h, 48h, 3 and 7 days following BCNI (n=3/group). MPGs were cultured in matrigel and neurite outgrowth measured. Erections were impaired early and improved by 60 days in BCNI rats. GDNF, NGF, BDNF and ATF3 gene expression was significantly increased and NT3 decreased in MPGs following BCNI (48h-21d; p<0.05). GDNF and NGF proteins levels were elevated in 48h BCNI. MPG neurite outgrowth from 24h and 48h BCNI was higher than sham (658±19μm; 607±24μm; 393±23μm, respectively, p<0.05). Further studies examining the roles of neurotrophic factors in modulating signaling pathways may provide therapeutic avenues for neurogenic-mediated ED.

M1 Macrophages Are Predominantly Recruited to the Major Pelvic Ganglion of the Rat Following Cavernous Nerve Injury

“…Our group has previously demonstrated an increase in gene expression of a variety of cytokines and chemokines in the MPG following BCNI [9,11,13]. In this study, we found that the gene expression of multiple pro-inflammatory cytokines and chemokines ( IL-1B, Il6, Tnfa, Tgfb, Ccl2, Ccr2) are up-regulated at 48 hours, 7 days, and 14 days after injury with maximal increase at 48 hours following BCNI.…”

“…TaqMan Gene Expression Assays (Applied Biosystems, Carlsbad, CA, USA) were used to evaluate the gene expression of CD11b (Rn00709342_m1), CD68 (Rn01495634_m1), CCL2 (Rn00580555_m1), CD86 (Rn00571654_m1), inducible nitric oxide synthase (iNOS: Rn00561646_m1), IL-6 (Rn01410330_m1), IL-1β (Rn00580432_m1), CD206 (Rn01487342_m1), IL-10 (Rn00563409_m1), and Arginase-1 (ARG1: Rn00691090_m1) and normalized to hypoxanthine guanine phosphoribosyl transferase (HPRT; Rn01527840_m1). All experiments were performed on 5 different whole MPGs from each group with triplicate technical replicate PCR reactions per sample [11]. M1/M2 index was used to evaluate the ratio of gene expression of M1 macrophage markers and M2 macrophage markers.…”

“…In the major pelvic ganglion (MPG), a number of pro-inflammatory cytokines and chemokines are increased as early as 24 to 48 hours after bilateral cavernous nerve injury (BCNI) in rodents [11,12]. This increase in pro-inflammatory cytokines and chemokines can alter macrophage phenotypes toward neurotoxic M1 macrophages [13].…”

Early-stage Type 2 Diabetes Mellitus Impairs Erectile Function and Neurite Outgrowth From the Major Pelvic Ganglion and Downregulates the Gene Expression of Neurotrophic Factors

“…All experiments were performed on 7 different whole paired MPGs from each group, with triplicate technical replicate PCR reactions per sample. 13 …”

“…MPGs were kept on ice in serum-free media (RPMI 1640 with 1% penicillin-streptomycin, GIBCO, Grand Island, NY) until they were embedded and cultured in reduced growth factor Matrigel (Corning, Tewksbury, MA) with vascular endothelial growth factor (VEGF; 25 μg/mL, R&D Systems, Minneapolis, MN) (n = 3 per group). 13 …”