Clinical, endocrinological and spermatological studies after endotoxin in the ram

Seminal and histopathological alterations in bucks challenged with Mannheimia haemolytica serotype a2 and its LPS endotoxin

Pneumonic mannheimiosis is a widespread respiratory bacterial disease of small ruminants caused by Mannheimia haemolytica serotype A2. The disease is known to affect the respiratory organs of infected animals, but its effect on other vital and reproductive organs has not been fully explored. Previous studies have demonstrated increased serum pro-inflammatory cytokine concentration post-challenge with M. haemolytica A2 and its LPS, indicating systemic inflammation in the host. This study determined the potential tissue changes and alterations of sperm parameters due to infection of M. haemolytica A2 and its LPS endotoxin. In this study, twelve experimental bucks were randomly assigned to three groups of four bucks each: group 1 (control group) were intranasally inoculated with 2 mL of PBS pH 7.0, group 2 received 2 mL of 1.2 × 10⁹ CFU/mL M. haemolytica A2 intranasally, and group 3 received 2 mL of LPS extracted from 1.2 × 10⁹ CFU/mL of M. haemolytica A2 intravenously. Semen samples were collected at pre-determined intervals using an electro-ejaculator and analysed immediately after collection. All experimental bucks were slaughtered via exsanguination on day 60 to collect their vital and reproductive organs at necropsy, and the samples were processed and analysed for histopathological changes. The current study has revealed that bucks challenged with M. haemolytica A2 and its LPS exhibited alterations in semen parameters such as motility, wave pattern, viability, and morphological abnormalities. Mild to moderate histopathological changes of the lung, liver, testis, epididymis, vas deferens, prostate, and lymph nodes were also observed in both challenged groups. Therefore, this study revealed the potential harmful effects of respiratory mannheimiosis on the reproductive organs of the infected bucks and sheds light on the expanse of systemic effects of this disease.

Association between Mannheimia haemolytica infection with reproductive physiology and performance in small ruminants: A review

Mannheimiosis or pneumonic pasteurellosis commonly occurs in small ruminants. Mannheimiosis is caused by Mannheimia haemolytica (M. haemolytica) a Gram-negative coccobacillus producing acute febrile and infectious condition resulting in death of animal if not diagnosed and treated promptly. M. haemolytica serotype A2 is a commensal of the nasopharynx, gaining access to the lungs when host defenses are compromised by stress or infection in small ruminants. Till date, there is a vast literature and research that has been conducted on the pathogenesis of M. haemolytica invariably on respiratory system and its related immune system and mechanisms. From the clinical point of view, infection or diseases involving vital organs will systemically affect the production and performance of the infected animal. Therefore, there is a huge gap of knowledge and research to answer the question whether there is any association between M. haemolytica infection with reproductive physiology and performance in small ruminants and how it affects the productivity level. This review will explore the possibilities of involvement and new potential research to be carried out to determine the involvement of male and female reproductive system with M. haemolytica infection among small ruminants.

Inflammatory networks in the control of spermatogenesis : chronic inflammation in an immunologically privileged tissue?

Spermatogenesis is a complex, organized process involving intimate interactions between the developing germ cells and supporting Sertoli cells. The process is also highly regulated. Studies suggest that regulation in the seminiferous epithelium involves molecules normally associated with either immune or inflammatory processes; in particular, interleukin 1a (IL1a), IL6, tumor necrosis factor (TNFa), activin A and nitric oxide (NO). While there is considerable evidence that these inflammatory mediators have effects on spermatogonial and spermatocyte development as well as critical supportive functions of the Sertoli cells, which are undoubtedly of considerable importance during testicular inflammation, there remains some skepticism regarding the significance of these molecules with respect to normal testicular function. Nonetheless, it is evident that expression of these regulators varies across the cycle of the seminiferous epithelium in a consistent manner, with major changes in production coinciding with key events within the cycle. This review summarizes the evidence supporting the hypothesis that inflammatory cytokines play a role in normal testicular spermatogenesis, as well as in the etiology of inflammation induced sub-fertility. The balance of data leads to the striking conclusion that the cycle of the seminiferous epithelium resembles a chronic inflammatory event. This appears to be a somewhat paradoxical assertion, since the testis is an immunologically privileged tissue based on its well-established ability to support grafts with minimal rejection responses. However, it may be argued that local immunoregulatory mechanisms, which confer protection from immunity on both transplanted tissues and the developing spermatogenic cells, are equally necessary to prevent local inflammation responses associated with the spermatogenic process from activating the adaptive immune response.

Effects of Flunixin Meglumine on Selected Clinicopathologic Variables, and Serum Testosterone Concentration in Stallions after Endotoxin Administration

Four clinically normal stallions were infused intravenously with endotoxin (LPS) from Escherichia coli 055:B5 at a dose of 0.3 microg/kg b.w. and four stallions were treated with flunixin meglumine (FM) as a single intravenous injection at a dose of 1.1 mg/kg b.w., 5 min after the infusion of LPS. In response to endotoxin infusion, stallions' reaction was fever (increased rectal and scrotal skin temperature), increased heart rate (HR) and leucopenia. Administration of endotoxin also influenced the level of testosterone (decrease at 3-24 h and increase at 48-72 h after LPS administration) in the blood serum. FM treatment prevented an endotoxin-induced increase in rectal and scrotal skin temperature, HR, with no influence on the decrease of leucocytes. Administration of FM only had a significant effect on the latter changes (at 24-72 h) of serum testosterone concentration after addition of endotoxin.

Study of the pathological effect of Escherichia coli endotoxin in rams

This experimental study was carried out on nine adult rams. Rams were injected intravenously with Escherichia coli endotoxin serotype 055:B5. The regimen of injections is described fully. Blood and semen samples were collected periodically to evaluate the changes in blood and semen picture. The reproductive as well as the visceral organs were collected and examined macroscopically and microscopically. The results of the study revealed that sperm cell abnormalities and serum testosterone level were increased, and sperm acrosomal abnormalities were significantly increased. The total leucocytic count was significantly decreased. The histopathological examination revealed severe testicular degeneration in addition to various other lesions in the visceral organs. Scanning electron microscope of the sperm cells revealed detached acrosomes, knobbed acrosomes and coiled tails.

Intrauterine infusion of bacterial lipopolysaccharide (LPS) prior to mating has no adverse effect on fertility, fetal survival and fetal development

Lipopolysaccharide (LPS, endotoxin) is a component of the cell wall of gram-negative bacteria and a potent inducer of severe inflammatory reactions. In mice, systemically administered LPS induces fetal resorption and increases fetal mortality. However, effects of intrauterine LPS on fertility, fetal survival and development have not been reported. In the present study, pigs were used to determine the effect of intrauterine infused LPS on fertility, fetal survival and development. Prior to mating, gilts received intrauterine infusion of either a single dose of saline or increasing doses of LPS in saline using an insemination catheter. On day 30 of pregnancy, gilts were hysterectomized and litter size, fetal length, number of corpora lutea (CL), ovarian and placental weights, and allantoic and amniotic fluid volumes were recorded. Blood progesterone levels from days 10-30 of pregnancy were also determined. Results indicated that intrauterine infusion of LPS had no adverse effects on blood progesterone levels, fertility, fetal survival or fetal development. Intrauterine injection of LPS did cause an increase in fetal weight and amniotic fluid volume (P < 0.05). These results suggest that sperm, oocytes and gametes are tolerant of local LPS challenge and, to some extent, this mechanism protects gametes and conceptuses from maternal response to mating introduced bacteria and their potential endotoxins.

Modulation of endotoxin-induced andrological alterations by flunixin meglumine in the boar

Flunixin meglumine (FM), an inhibitor of the cyclo-oxygenase pathway of the prostaglandin synthesis, was used to evaluate the andrological changes following an endotoxin (ET) administration in the boar. FM was injected as a single dose 10 min prior to an ET injection. Blood plasma was analysed for the contents of 15-ketodihydroprostaglandin (PG) F2 alpha LH, testosterone and cortisol. Twelve h after the ET administration, the boars were castrated and the testes examined by light and electron microscopy. The results were compared between controls, ET-, FM- and FM+ET-treated boars. An increase in 15-ketodihydro-PGF2 alpha levels was seen following ET administration. Pretreatment with FM decreased the levels of 15-ketodihydro-PGF2 alpha during 2 h. Following the ET administration a voluminous increase in testosterone levels as well as changed LH levels were seen. Similar alterations in hormonal levels were observed also after pretreatment with FM, however, delayed about 2 h, and during this time a marked decrease in testosterone levels was seen. In the testes an infiltration of polymorphonuclear neutrophils (PMN) in the interstitium and histological changes among the Leydig cells were seen after ET injection. Pretreatment with FM reduced the number of invading PMN and the Leydig cells appeared less affected. The results show that FM modulated the negative effects of ET on the testicular function in the boar, indicating that the initiation of the arachidonic acid cascade was of importance for the induction of the alterations following an ET injection.

Alterations in testicular function after endotoxin injection in the boar

Twelve mature boars were injected intravenously with endotoxin from Salmonella typhimurium. Blood plasma was analysed for 15-ketodihydro-PGF2 alpha, LH and testosterone. The boars were castrated at various times after endotoxin administration and the testes examined by light and electron microscopy. The levels of 15-ketodihydro-PGF2 alpha and LH rose immediately after endotoxin injection followed by an increase in testosterone levels, and in five boars a second increase in LH levels was observed. Morphological examination of the testes revealed infiltration of polymorphonuclear neutrophils (PMN) into the testicular interstitium. The Leydig and myoid cells showed morphological changes. Alterations were also present in the seminiferous epithelium among Sertoli cells, spermatocytes and spermatids. The results indicate that endotoxins can exert a negative effect on testicular function in the boar. Except for the initial increase in LH levels, which is not clearly understood, the hormonal changes are thought to be mediated by alterations in Leydig cell function. The alterations further support previous findings in the boar, and indicate that there is short-term, moderate damage to the seminiferous epithelium following endotoxin injection.

Experimentally induced testicular alterations in boars: hormonal changes in mature and peripubertal boars

Eleven sexually mature boars and 10 peripubertal boars were used to study the effects of elevated testicular temperature on plasma hormonal levels. The scrotum of the boars was covered with a textile-aluminium foil insulation device for 100 h. Insulation of the scrotum in the peripubertal boars took place at an age of 100 days. Blood samples were drawn 3 times daily for 12 days in the mature boars, starting 3 days before scrotal insulation. In the peripubertal boars, blood sampling was performed once a day for 11 days, starting the first day of scrotal insulation. During scrotal insulation, the plasma levels of testosterone, oestradiol-17 beta and oestrone sulphate decreased continuously in the mature boars. After removal of the scrotal insulation device there was a continuously increase, back to normal levels of oestradiol-17 beta and oestrone sulphate. The plasma levels of testosterone showed an immediate rise of brief duration after removal of the device in 5 of the boars, while in the other 6 boars the rise in testosterone levels came 4 days after removal and lasted for 3 days. In the peripubertal boars, there were no significant differences in the hormone levels between the experimental and control animals during and after scrotal insulation. However, the decrease in testosterone concentration over time, during scrotal insulation, was significant within the experimental group.