Hi all,
I have a question about the von Frey assay (or really, any nociceptive assay where multiple animals are in close spatial proximity). I am using both male and female mice now, rather than just all males, as I used to do. But I'm wondering whether I should do my testing of both sexes simultaneously (both sexes on the testing apparatus at the same time), or staggered in time (so that only one sex is on the apparatus at a time). My concern is potential male-female influence (via odors or sounds). What do you think?
Crossposted at Pain Researcher
http://forum.painresearcher.net/t/do-you-test-male-and-female-mice-rats-at-the-same-time-in-the-same-place-or-separate-over-time/29/4
Great question. A study in Nature a couple years ago found that male olfactory cues (male mice, bedding in contact with male mice, human male experimenters, men's used
A study in Nature a couple years ago found that male olfactory cues (male mice, bedding in contact with male mice, human male experimenters, men's used tshirts) led to stress-induced analgesia in both male and female mice, but to a higher degree in the latter.
In short, yes, male smell likely has an effect, but it also did when you were only testing males and either way by being a male researcher you're likely already triggering these effects to some degree.
Edit: Here is a link to the article, in Nature Methods not Nature (my bad).
http://www.nature.com/nmeth/journal/v11/n6/full/nmeth.2935.html
There are other factors to be taken into account, for example if they are housed jointly or in separate rooms, if the female animals are ooforectomized, the time of the light/dark cycle they are housed at or the type of pain inducing method you are experimenting on. All of those may be altered by the gender difference.
Anyway, in order to exclude variables as much as possible I would recommend not to test them together unless you are trying to establish an effect.
Hi Alexander,
In case of doubt and in order to avoid the bias that could result from the effect of the presence of males in the female response to Von Frey filaments, I highly recommend to test them separately. Otherwise you could compromise your data. Take in consideration the study suggested by Alberto.
All the best,
extremely important questions - also since we know that transgender interaction is also a factor in uhuman experiments onpain sensitivity. The role of odor has been correctly highlighted by Alberto and also the Impact of odors on gonodal hormones by Abraham. MIce should be extremely sensitive since they are essentially a very non-social type of animal and social interaction is much more likely to be a stressor (compared to, let's say, rats).Also, the majority of mouse studies are done in CL6/57B mice, which are by breeding selection altered in their sleep behavior (they are lacking L-Melatonin as a sleep-inducing Hormone; thus, chronicqally sleep-deprived, which is an eminent stress-prone condition).
Frankly, a study showing should explore mice a different gender tested together or gender-stratied in mice which have been housed gender-separated or even grown up that way in a fully randomized block design study. If you volunteered to do such a study that will be highly appreciated by the community (Gender is always a big Topic in pain Research, but conspicuously understudied), Kind regards
Today is the good day to you, Alexander ! It is very interesting discussion on the matter. In our laboratory male and female, mice or rats, housed separately in different rooms to avoid the unwonted influence via odors, ferramons and vocalization between the animals of different genders. However, you can perform a study about the male/female interaction concerning the pain or tactile (von Frey test) sensitivity in these rodents. Best wishes.
Walter's request to test for the block tests would be welcome by the community.
Some answers over on Pain Researcher
http://forum.painresearcher.net/t/do-you-test-male-and-female-mice-rats-at-the-same-time-in-the-same-place-or-separate-over-time/29/4
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