Why do a rat's testicles swell? - briefly
Swelling usually indicates inflammation caused by infection, trauma, or torsion, which leads to fluid buildup and edema. Hormonal changes or exposure to toxic substances can also produce testicular enlargement in rats.
Why do a rat's testicles swell? - in detail
Testicular enlargement in laboratory rodents results from distinct physiological and pathological mechanisms. Normal reproductive activity can produce transient swelling when spermatogenesis intensifies; increased blood flow to the scrotal plexus and fluid accumulation within the interstitial tissue raise the organ’s volume. Hormonal fluctuations, especially elevated luteinizing hormone and testosterone, can amplify vascular permeability and cause mild, reversible edema.
Pathological conditions generate more pronounced and persistent swelling. Common causes include:
- Inflammation: bacterial or fungal orchitis, epididymitis, and abscess formation lead to leukocyte infiltration, cytokine release, and exudate accumulation.
- Infection: systemic pathogens such as Salmonella spp. or Streptococcus spp. can invade testicular tissue, producing purulent discharge and marked enlargement.
- Trauma: blunt force or accidental crushing results in hemorrhage, hematoma, and subsequent edema.
- Vascular disorders: varicocele or thrombosis of the pampiniform plexus impedes venous return, raising hydrostatic pressure and causing fluid buildup.
- Neoplasia: seminomas, Leydig cell tumors, and mixed germ‑cell neoplasms generate solid masses that expand the scrotum.
- Hydrocele: excess serous fluid within the tunica vaginalis accumulates due to impaired drainage, producing a smooth, fluctuant swelling.
- Torsion: twisting of the spermatic cord restricts arterial inflow and venous outflow, leading to ischemia, edema, and rapid enlargement.
Diagnostic evaluation relies on gross inspection, palpation, and imaging. Ultrasonography distinguishes solid masses from fluid collections, while cytology or histopathology confirms infectious or neoplastic origins. Blood work assesses inflammatory markers and hormone levels, providing additional context for the swelling’s etiology.
Management strategies correspond to the underlying cause. Antimicrobial therapy treats bacterial orchitis; surgical correction resolves torsion, varicocele, or tumor removal; anti‑inflammatory agents reduce edema from trauma or sterile inflammation; and supportive care—temperature regulation and analgesia—facilitates recovery in non‑critical cases. Continuous monitoring of testicular size and animal behavior ensures early detection of recurrence or complications.