Hypogonadism induced by surgical stress and brain trauma is reversed by human chorionic gonadotropin in male rats: A potential therapy for surgical and TBI-induced hypogonadism?

Introduction: Hypogonadotropic hypogonadism (HH) is an almost universal, yet underappreciated, endocrinological complication of traumatic brain injury (TBI). The goal of this study was to determine whether the developmental hormone human chorionic gonadotropin (hCG) treatment could reverse HH induced by a TBI. Methods: Plasma samples were collected at post-surgery/post-injury (PSD/PID) days -10, 1, 11, 19 and 29 from male Sprague-Dawley rats (5- to 6-month-old) that had undergone a Sham surgery (craniectomy alone) or CCI injury (craniectomy + bilateral moderate-to-severe CCI injury) and treatment with saline or hCG (400 IU/kg; i.m.) every other day. Results: Both Sham and CCI injury significantly decreased circulating testosterone (T), 11-deoxycorticosterone (11-DOC) and corticosterone concentrations to a similar extent (79.1% vs. 80.0%; 46.6% vs. 48.4%; 56.2% vs. 32.5%; respectively) by PSD/PID 1. hCG treatment returned circulating T to baseline concentrations by PSD/PID 1 (8.9 ± 1.5 ng/ml and 8.3 ± 1.9 ng/ml; respectively) and was maintained through PSD/PID 29. hCG treatment significantly, but transiently, increased circulating progesterone (P4) ~3-fold (30.2 ± 10.5 ng/ml and 24.2 ± 5.8 ng/ml) above that of baseline concentrations on PSD 1 and PID 1, respectively. hCG treatment did not reverse hypoadrenalism following either procedure. Conclusions: Together, these data indicate that (1) craniectomy is sufficient to induce persistent hypogonadism and hypoadrenalism, (2) hCG can reverse hypogonadism induced by a craniectomy or craniectomy +CCI injury, suggesting that (3) craniectomy and CCI injury induce a persistent hypogonadism by decreasing hypothalamic and/or pituitary function rather than testicular function in male rats. The potential role of hCG as a cheap, safe and readily available treatment for reversing surgery or TBI-induced hypogonadism is discussed

Conjugated linoleic acid administration induces amnesia in male sprague dawley rats and exacerbates recovery from functional deficits induced by a controlled cortical impact injury

Long-chain polyunsaturated fatty acids like conjugated linoleic acids (CLA) are required for normal neural development and cognitive function and have been ascribed various beneficial functions. Recently, oral CLA also has been shown to increase testosterone (T) biosynthesis, which is known to diminish traumatic brain injury (TBI)-induced neuropathology and reduce deficits induced by stroke in adult rats. To test the impact of CLA on cognitive recovery following a TBI, 5–6 month old male Sprague Dawley rats received a focal injury (craniectomy + controlled cortical impact (CCI; n = 17)) or Sham injury (craniectomy alone; n = 12) and were injected with 25 mg/kg body weight of Clarinol® G-80 (80% CLA in safflower oil; n = 16) or saline (n = 13) every 48 h for 4 weeks. Sham surgery decreased baseline plasma progesterone (P4) by 64.2% (from 9.5 ± 3.4 ng/mL to 3.4 ± 0.5 ng/mL; p = 0.068), T by 74.6% (from 5.9 ± 1.2 ng/mL to 1.5 ± 0.3 ng/mL; p \u3c 0.05), 11-deoxycorticosterone (11-DOC) by 37.5% (from 289.3 ± 42.0 ng/mL to 180.7 ± 3.3 ng/mL), and corticosterone by 50.8% (from 195.1 ± 22.4 ng/mL to 95.9 ± 2.2 ng/mL), by post-surgery day 1. CCI injury induced similar declines in P4, T, 11-DOC and corticosterone (58.9%, 74.6%, 39.4% and 24.6%, respectively) by post-surgery day 1. These results suggest that both Sham surgery and CCI injury induce hypogonadism and hypoadrenalism in adult male rats. CLA treatment did not reverse hypogonadism in Sham (P4: 2.5 ± 1.0 ng/mL; T: 0.9 ± 0.2 ng/mL) or CCI-injured (P4: 2.2 ± 0.9 ng/mL; T: 1.0 ± 0.2 ng/mL, p \u3e 0.05) animals by post-injury day 29, but rapidly reversed by post-injury day 1 the hypoadrenalism in Sham (11-DOC: 372.6 ± 36.6 ng/mL; corticosterone: 202.6 ± 15.6 ng/mL) and CCI-injured (11-DOC: 384.2 ± 101.3 ng/mL; corticosterone: 234.6 ± 43.8 ng/mL) animals. In Sham surgery animals, CLA did not alter body weight, but did markedly increase latency to find the hidden Morris Water Maze platform (40.3 ± 13.0 s) compared to saline treated Sham animals (8.8 ± 1.7 s). In CCI injured animals, CLA did not alter CCI-induced body weight loss, CCI-induced cystic infarct size, or deficits in rotarod performance. However, like Sham animals, CLA injections exacerbated the latency of CCI-injured rats to find the hidden MWM platform (66.8 ± 10.6 s) compared to CCI-injured rats treated with saline (30.7 ± 5.5 s, p \u3c 0.05). These results indicate that chronic treatment of CLA at a dose of 25 mg/kg body weight in adult male rats over 1-month 1) does not reverse craniectomy- and craniectomy + CCI-induced hypogonadism, but does reverse craniectomy- and craniectomy + CCI-induced hypoadrenalism, 2) is detrimental to medium- and long-term spatial learning and memory in craniectomized uninjured rats, 3) limits cognitive recovery following a moderate-severe CCI injury, and 4) does not alter body weight

Correction: Conjugated Linoleic Acid Administration Induces Amnesia in Male Sprague Dawley Rats and Exacerbates Recovery from Functional Deficits Induced by a Controlled Cortical Impact Injury.

[This corrects the article DOI: 10.1371/journal.pone.0169494.]

CCI, but not CLA, reduces body weight.

<p>Body weight (as a % of baseline weight) each day from PID -10 to PID 29 for Sham + saline (n = 5), Sham + CLA (n = 7), CCI + saline (n = 8) and CCI + CLA (n = 9) groups. Data were analyzed using 2-way repeated measures ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test (p < 0.05; letters indicate differences between pre- and post-surgery body weights between groups across the experiment).</p

Chronic CLA administration compromises short-medium term learning and memory in both uninjured and CCI-injured rats as assessed by latency to locate the Morris water maze (MWM) following novel platform placement.

<p>Second Run: Five minutes after Run 1 (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169494#pone.0169494.g004" target="_blank">Fig 4</a>), latency in seconds to reach the hidden platform at PID 6–10 (Acquisition Phase; platform in SE quadrant) and at PID’s 20–22 (Re-acquisition Phase; platform changed to NE quadrant, ‘Novel Platform Placement’) was tested. MWM Run 2 latency data (mean ± SEM) on PID’s 6–10 and 21–22 were analyzed from 29 rats as follows: Sham + saline (n = 5), Sham + CLA (n = 7), CCI + saline (n = 8) and CCI + CLA (n = 9). Data were analyzed using 2-way repeated measures ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test (p < 0.05; a, b, c and d = differences between time and group, e = differences within groups between the acquisition (PID 10) and re-acquisition phases (PID 20)).</p

CLA does not restore CCI-induced decreases in circulating sex hormone concentrations.

<p>Plasma concentrations (mean ± SEM) of P₄, T, 11-DOC and corticosterone (ng/mL) at PID’s -10, 1, 11, 19 and 29 for Sham + saline (n = 5), Sham + CLA (n = 5), CCI + saline (n = 8) and CCI + CLA (n = 5) groups. Data were analyzed using 2-way repeated measures ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test (p < 0.05, letters indicate differences between post-injury days and treatments for T, 11-DOC and corticosterone; for P₄, results did not reach significance for main effect of post-injury day or treatment, p = 0.068).</p

CLA does not reduce gross lesion size following a CCI.

<p>Top: Representative figures for each group, illustrating lesion size 1-month post-CCI. Bottom: Lesion size depicted as a percentage of surface area damaged (y-axis) for rats in each surgery/treatment group (x-axis). Gross lesion size data (mean ± SEM) at PID 29 were analyzed from 29 rats as follows: Sham + saline (n = 5), Sham + CLA (n = 7), CCI + saline (n = 8) and CCI + CLA (n = 9). Data were analyzed using ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test (p < 0.01; letter indicates differences between groups).</p

Chronic CLA administration is detrimental to medium-long term spatial memory.

<p><u>Probe Test 1:</u> At the end of each acquisition phase, the platform was removed (from the NE quadrant) and 48 h later the animals were tested in the MWM for NE quadrant preference over 60 s to determine if they remembered the location of the hidden platform. <u>Probe Test 2:</u> Likewise, after completing the re-acquisition phase the platform was removed from the SE quadrant and 48 h later the animals were tested for SE (new location), NE (old location) and SE + NE quadrant preferences (both new and old locations). MWM duration in target quadrant(s) data (mean ± SEM) during Probe Test 1 and 2 were analyzed from 29 rats as follows: Sham + saline (n = 5), Sham + CLA (n = 7), CCI + saline (n = 8) and CCI + CLA (n = 9). Data were analyzed by ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test (p < 0.05; a, b, c and d = differences between time and group, e = differences within groups between the acquisition (PID 10) and re-acquisition phases (PID 20)).</p

CLA does not improve vestibulomotor function following CCI.

<p>Rats were placed on a rotating rod accelerating at a constant rate (1 rotation per second per second) and allowed to run for up to 300 s at PID’s -3, 2, 6, 9, 13 and 23. Time elapsed (seconds) before fall was recorded. Rotarod latency data (mean ± SEM) on PID’s 6–10 and 21–22 were analyzed from 29 rats as follows: Sham + saline (n = 5), Sham + CLA (n = 7), CCI + saline (n = 8) and CCI + CLA (n = 9). Data were analyzed using 2-way repeated measures ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test; letters indicate differences between groups and times compared to baseline and sham groups, <i>p</i> < 0.05.</p

Chronic CLA administration compromises medium-long term learning and memory in both uninjured and CCI-injured rats as assessed by latency to locate the Morris water maze (MWM) platform.

<p>First Run: Latency in seconds to reach the hidden platform at PID’s 6–10 (Acquisition Phase; platform in SE quadrant) and at PID 20–22 (Re-acquisition Phase; platform changed to NE quadrant, ‘Novel Platform Placement’). MWM Run 1 latency data (mean ± SEM) on PID’s 6–10 and 21–22 were analyzed from 29 rats as follows: Sham + saline (n = 5), Sham + CLA (n = 7), CCI + saline (n = 8) and CCI + CLA (n = 9). Data were analyzed using 2-way repeated measures ANOVA; post-hoc analyses were performed using the Tukey multiple comparison test (p < 0.05; a, b, c and d = differences between time and group, e = differences within groups between the acquisition (PID 10) and re-acquisition phases (PID 20)).</p