Altered brain activity associated with premature ejaculation improved by electroacupuncture in rats

Abstract

Background: Premature ejaculation (PE) is linked with abnormal brain activity that is modifiable by electroacupuncture (EA).

Aim: In this study we aimed to explore the central pathological mechanism underlying EA in treating PE.

Methods: Six-week-old male Sprague-Dawley rats were divided into a PE group (n = 8) and a control group (n = 8) according to ejaculatory frequency during copulatory behavior. All rats underwent EA at the Zusanli acupoint (ST-36) for 4 weeks. Magnetic resonance imaging data were collected before and after EA.

Outcomes: The behavioral parameters, plasma norepinephrine levels, fractional amplitude of low frequency fluctuation (fALFF), and regional homogeneity (ReHo) were evaluated.

Results: The PE group ejaculated more times with shorter latency compared with controls. After EA, the ejaculation frequency of the PE group decreased, and the ejaculation latency period increased, with no changes observed in the control group. Norepinephrine levels were higher in the PE group than in the controls and were positively correlated with ejaculation frequency and negatively correlated with ejaculation latency. The PE group showed lower fALFF in the right striatum and higher ReHo in the brainstem compared with controls. After EA, controls showed decreased fALFF in the right striatum, left olfactory bulb, and dorsal fornix and increased ReHo in the right interpeduncular nucleus, as well as decreased ReHo in the left striatum, prelimbic system, right basal forebrain region, septal region, and olfactory bulb, while the model group exhibited increased fALFF in the right hypothalamic region, decreased fALFF in the left globus pallidum and right basal forebrain region and increased ReHo in the right interpeduncular nucleus, as well as decreased ReHo in the left striatum, olfactory bulb, basal forebrain region, dentate gyrus, right dysgranular insular cortex, and striatum. Compared with the controls after EA, the model group showed increased ReHo of the right hypothalamic region and decreased ReHo of the right dysgranular insular cortex.

Clinical implications: These findings might enhance the understanding of PE and contribute to new, targeted therapies for PE.

Strengths and limitations: The therapeutic effects might be achieved by EA inhibiting the activity in brain regions involved in ejaculatory behavior. However, the curative effect of acupuncture might be underestimated due to some curative effects of sham acupuncture used in the control group.

Conclusion: In conclusion, the ejaculatory frequency of rats may be reduced and ejaculation latency could be extended by EA at ST-36, which might be achieved by the effects of this treatment on brain activity.

Keywords: electroacupuncture; fractional amplitude of low frequency fluctuation; functional magnetic resonance imaging; premature ejaculation; regional homogeneity; resting-state.