Sequential mesenteric lymph node histological response following Trichinella spiralis infection

Area of Science:

• Immunology
• Parasitology
• Histopathology

Background:

• Trichinella spiralis is an intestinal nematode parasite.
• Secondary lymphoid organs play a crucial role in immune responses to pathogens.
• Understanding the host's histological response to infection is vital.

Purpose of the Study:

• To investigate the histological alterations in mouse mesenteric lymph nodes following Trichinella spiralis infection.
• To document the temporal dynamics of lymphoid tissue changes during the infection course.

Main Methods:

• ICR/CD-1 mice were infected orally with 200 Trichinella spiralis larvae.
• Mesenteric lymph nodes were collected at 0, 3, 7, 14, 28, and 56 days post-infection.
• Tissues were processed for routine paraffin embedding and histological examination of 4-micron sections.

Main Results:

• Hyperplasia of lymphoid tissue was observed as early as 3 days post-infection.
• Progressive changes, including medullary sinus congestion and increased immune cell infiltration (neutrophils, histiocytes, lymphocytes, eosinophils), occurred between 7 and 28 days.
• By 56 days post-infection, lymph node histology returned to resemble control tissues.

Conclusions:

• Trichinella spiralis infection induces significant, yet transient, histological changes in the mesenteric lymph nodes of mice.
• The observed hyperplasia and immune cell influx indicate an active immune response to the parasite.
• The resolution of histological alterations by day 56 suggests the parasite is cleared or contained, and the lymphoid tissue recovers.