Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion

Abstract

Axonal injury due to prostatectomy leads to Wallerian degeneration of the cavernous nerve (CN) and erectile dysfunction (ED). Return of potency is dependent on axonal regeneration and reinnervation of the penis. Following CN injury (CNI), RhoA and Rho-associated protein kinase (ROCK) increase in penile endothelial and smooth muscle cells. Previous studies indicate that nerve regeneration is hampered by activation of RhoA/ROCK pathway. We evaluated the role of RhoA/ROCK pathway in CN regulation following CNI using a validated rat model. CNI upregulated gene and protein expression of RhoA/ROCK and caspase-3 mediated apoptosis in the major pelvic ganglion (MPG). ROCK inhibitor (ROCK-I) prevented upregulation of RhoA/ROCK pathway as well as activation of caspase-3 in the MPG. Following CNI, there was decrease in the dimer to monomer ratio of neuronal nitric oxide synthase (nNOS) protein and lowered NOS activity in the MPG, which were prevented by ROCK-I. CNI lowered intracavernous pressure and impaired non-adrenergic non-cholinergic-mediated relaxation in the penis, consistent with ED. ROCK-I maintained the intracavernous pressure and non-adrenergic non-cholinergic-mediated relaxation in the penis following CNI. These results suggest that activation of RhoA/ROCK pathway mediates caspase-3 dependent apoptosis of nitrergic neurons in the MPG following CNI and that ROCK-I can prevent post-prostatectomy ED.

Impaired contraction and decreased detrusor innervation in a female rat model of pelvic neuropraxia

“…The nerve terminal data parallel previous studies showing decreased VAChT expression in bladder wall and pelvic plexus 10 days post-injury [18]. Additionally, in male rats undergoing cavernous nerve injury VAChT gene expression was transient in the major pelvic ganglia as it initially decreased early (2, 7 days) and at late time points (30, 60 days) following injury [26]. In this study, at 14 and 30 days following injury there were also significant declines in nNOS and adrenergic (TH positive) nerve terminals.…”

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

“…Rats were randomly separated into 4 groups (n=10/group): (i) Sham; (ii) BCNI 48 hours (BCNI-48h); (iii) BCNI 7 days (BCNI-7d); (iv) BCNI 14 days (BCNI-14d). The MPGs and penises of the Sham, BCNI-48h, BCNI-7d and BCNI-14d were harvested after surgery as previously described [14,15]. All the experiments were conducted in accordance with the XXXXX Guidelines for Animal Care and Use, and the National Institute of Health Guide for the Care and Use of Laboratory Animals.…”

“…To induce BCNI, both CNs (2–3 mm distal to MPG) were crushed with Dumont #5 forceps. The forceps were closed completely 3 times for 15 seconds each [15]. The same surgeon performed all the BCNI surgeries.…”

“…The penises were carefully removed (length: 10 mm) and placed in a physiological Krebs solution (130 mM NaCl, 4.7 mM KCl, 1.56 mM CaCl 2 , 1.18 mM MgSO 4 , 1.18 mM KH 2 PO 4 , 14.9 mM NaHCO 3 , and 5.6 mM dextrose ) [15–17]. Under a dissecting microscope, the urethras including the corpus spongiosum, the dorsal nerves, the dorsal arteries, the dorsal veins, and the glans were carefully removed from the penises.…”

Fasudil Attenuates LPS-Induced Acute Lung Injury by Preventing Endothelial Dysfunction

“…Moreover, in cultured human PMECs, fasudil sufficiently inhibited LPS-induced activation of apoptosis executor caspase-3, accompanied by ROCK activation. Inhibition of the ROCK pathway by fasudil has been reported to prevent apoptosis through direct or indirect inhibition of caspase-3 [26,27]. Previous studies have suggested that ROCK activation evoked caspase-3 cleavage via up-regulating the expression of Bax and Bclxl [28] and depending on myosin-mediated contraction [29] in different cell types.…”