The effect of spinal cord injury on sexual function.

Abstract

Spinal cord injury (SCI) causes severe neurological impairment with widespread motor, autonomic and sensory deficits, leading to a substantial quality of life impairment. The number of individuals with SCI increases by approximately 12,500 annually, and over 80% of individuals with SCI are males. SCI individuals rate sexual function as a top priority quality of life issue, and men with SCI likely suffer from sexual dysfunction, such as erectile and ejaculatory dysfunction, as well as infertility. Regardless of the high status of importance of sexual function, limited numbers of experimental studies in SCI animal models have focused on sexual function after SCI. Interestingly, human clinical research participants with SCI undergoing daily locomotor treadmill training have reported changes in sexual function. To advance targeted recovery of sexual function after SCI, a better understanding of the post-injury neural circuitry is necessary. The objective of this project was to determine the effect of activity-based training (ABT) on sexual function in a rat model of SCI and examine the effects of a contusion SCI on sexual function using improved quantifiable measures. Two wellestablished measures of sexual function were used to determine the effects of ABT on sexual function after SCI: the penile dorsiflexion reflex (PDFR) and vi bulbospongiosus electromyography. The second and third studies focused on determining the effect of a clinically relevant contusion injury of varying severities using kinematic analysis of the PDFR and real-time intracavernosal pressure recordings from the penis of rats undergoing mating behavior testing. ABT was shown to positively affect sexual function after SCI, where taskspecific stepping and/or hindlimb loading impacts the local spinal cord circuitry responsible for sexual function. ABT may strengthen the residual fibers crossing the lesion epicenter, providing better coordination of supraspinal influences on the spinal cord sexual circuitry. Sexual function after SCI was determined to be correlated with the percent of white matter spared (a measure of injury severity), further supporting the disruption of spinobulbospinal coordination as the cause of sexual dysfunction after SCI. Kinematic analysis of the penile dorsiflexion reflex and telemetric recording of intracavernosal pressure may provide improved quantifiable measures for examining sexual function after SCI.

Sex Differences in Pubertal Circadian and Ultradian Rhythmic Development Under Semi-naturalistic Conditions

“…A commercially available fE2 ELISA kit was used to quantify E2 in fecal samples (Arbor Assays). These assays have been previously published in species ranging from rats and mice (Asimes et al, 2018; Auer et al, 2020; Kalliokoski et al, 2015; Lv et al, 2020; Mathew et al, 2017; Steadman, 2019; Steadman et al, 2019), to wolves (Franklin et al, 2020), to humans (Righetti et al, 2020). ELISAs were conducted according to the manufacturer’s instructions.…”

Sex Differences in Pubertal Circadian and Ultradian Rhythmic Development Under Naturalistic Conditions

“…A commercially available fE2 enzyme-linked immunosorbent assay (ELISA) kit was used to quantify E2 in fecal samples (Arbor Assays, Ann Arbor, MI). These assays have been previously published in species ranging from rats and mice(Asimes et al, 2018; Auer et al, 2020; Kalliokoski et al, 2015; Lv et al, 2020; Mathew et al, 2017; Steadman, 2019; Steadman et al, 2019), to wolves(Franklin et al, 2020), to humans(Righetti et al, 2020). ELISAs were conducted according to the manufacturer’s instructions.…”