Report on the use of Warm Stages in UK Fertility Laboratories to Assess Sperm Viability

Animal fertility assessment is crucial for animal husbandry in the UK: farmers need to know that their breeding animals are healthy before the breeding season so that lambing and calving can be organised effectively. Linkam warms stages are designed to hold a specified temperature to +/- 0.1°C from ambient to 60°C. They are an accurate temperature control platform for inverted or upright microscope applications where it is crucial to maintain at 0.1°C stable temperature in the sample whether mounted in a petri dish or on a microscope slide.

Sperm motility is temperature dependent. To establish in-vivo fertility, observations need to be carried out at body temperature to mimic conditions within the body: for humans, bulls and rams is exactly 37°C. The use of a precise, accurate heated warm stage is an essential part of the assessment. This is to ensure the assessment is conducted at a stable and specific temperature. Within the design of this Linkam warm stage, a platinum resistor temperature sensor is used for higher accuracy and stability. A sophisticated CAD designed bi-filar heating element covers the entire working surface which provides a uniform temperature distribution in the sample slide.

A sample is placed onto a clean glass slide and covered with a coverslip to provide a chamber. The weight of the cover slip spreads the sample evenly. Scientists initially look for aggregation or agglutination, and the presence of non-spermatozoa cells. The preparation is then observed at 400x magnification with a phase contrast microscope to observe motility. Each Linkam-designed warm plate is incredibly thin, as little as 0.5mm. This ensures that high resolution objective and condenser lenses can be used. Approximately 200 spermatozoa are counted and categorised to determine the percentage of each category. Spermatozoa can be classified as progressively motile, non-progressively motile or non-motile. The percentage of progressively motile sperm is important to fertility assessment.

Linkam warm stages are found in cell biology labs, veterinary hospitals, hospitals and IVF clinics all over the world. The Linkam warm stages provide a simple, accurate, low cost temperature controlled platform that can heat/cool samples from ambient to 60°C.